SELECT 
  `P`.`product_id`, 
  `PFD`.`internal_name` AS `name`, 
  `PFVD`.`variant`, 
  `PFVD`.`variant_id`, 
  `PFD`.`feature_id` 
FROM 
  `cscart_product_features_values` AS `PFV` 
  JOIN `cscart_product_features` AS `PF` ON `PFV`.`feature_id` = `PF`.`feature_id` 
  JOIN `cscart_products` AS `P` ON `P`.`product_id` = `PFV`.`product_id` 
  JOIN `cscart_product_features_descriptions` AS `PFD` ON `PFV`.`feature_id` = `PFD`.`feature_id` 
  JOIN `cscart_product_feature_variants` AS `PFVS` ON `PFVS`.`variant_id` = `PFV`.`variant_id` 
  JOIN `cscart_product_feature_variant_descriptions` AS `PFVD` ON `PFVS`.`variant_id` = `PFVD`.`variant_id` 
WHERE 
  1 
  AND `PF`.`status` = 'A' 
  AND `PFV`.`product_id` IN('14253')

Query time 0.00071

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "7.46"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "P",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY",
            "cscart_products_product_id_index"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.10",
            "prefix_cost": "0.00",
            "data_read_per_join": "7K"
          },
          "used_columns": [
            "product_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "PFV",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "variant_id",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "product_id",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 5,
          "rows_produced_per_join": 5,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "0.51",
            "eval_cost": "0.50",
            "prefix_cost": "1.01",
            "data_read_per_join": "3K"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id"
          ],
          "attached_condition": "(`dev2`.`PFV`.`product_id` = '14253')"
        }
      },
      {
        "table": {
          "table_name": "PF",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY",
            "status"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "feature_id"
          ],
          "key_length": "3",
          "ref": [
            "dev2.PFV.feature_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 4,
          "filtered": "80.46",
          "cost_info": {
            "read_cost": "1.25",
            "eval_cost": "0.40",
            "prefix_cost": "2.76",
            "data_read_per_join": "6K"
          },
          "used_columns": [
            "feature_id",
            "status"
          ],
          "attached_condition": "(`dev2`.`PF`.`status` = 'A')"
        }
      },
      {
        "table": {
          "table_name": "PFVS",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id"
          ],
          "key_length": "3",
          "ref": [
            "dev2.PFV.variant_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 4,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "1.47",
            "eval_cost": "0.40",
            "prefix_cost": "4.64",
            "data_read_per_join": "6K"
          },
          "used_columns": [
            "variant_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "PFVD",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "variant_id"
          ],
          "key_length": "3",
          "ref": [
            "dev2.PFV.variant_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 4,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "1.01",
            "eval_cost": "0.40",
            "prefix_cost": "6.04",
            "data_read_per_join": "17K"
          },
          "used_columns": [
            "variant_id",
            "variant"
          ]
        }
      },
      {
        "table": {
          "table_name": "PFD",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "feature_id"
          ],
          "key_length": "3",
          "ref": [
            "dev2.PFV.feature_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 4,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "1.01",
            "eval_cost": "0.41",
            "prefix_cost": "7.46",
            "data_read_per_join": "11K"
          },
          "used_columns": [
            "feature_id",
            "internal_name"
          ]
        }
      }
    ]
  }
}

Result

product_id name variant variant_id feature_id
14253 Мощность двигателя, л.с. 273 8764 737
14253 Шины 425/85 R21 9218 745
14253 Объем топливного бака, л. 300 9494 746
14253 Максимальная скорость, км/ч 85 9137 748
14253 Количество мест в автобусе 22 13583 750