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(
    '14469', '14718', '13922', '14055', 
    '8254'
  )

Query time 0.00084

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "33.61"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "PFV",
          "access_type": "range",
          "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",
          "rows_examined_per_scan": 19,
          "rows_produced_per_join": 19,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "2.28",
            "eval_cost": "1.90",
            "prefix_cost": "4.18",
            "data_read_per_join": "14K"
          },
          "used_columns": [
            "feature_id",
            "product_id",
            "variant_id"
          ],
          "attached_condition": "(`dev2`.`PFV`.`product_id` in ('14469','14718','13922','14055','8254'))"
        }
      },
      {
        "table": {
          "table_name": "P",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY",
            "cscart_products_product_id_index"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "ref": [
            "dev2.PFV.product_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 19,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "4.75",
            "eval_cost": "1.90",
            "prefix_cost": "10.83",
            "data_read_per_join": "143K"
          },
          "used_columns": [
            "product_id"
          ]
        }
      },
      {
        "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": 15,
          "filtered": "80.46",
          "cost_info": {
            "read_cost": "4.75",
            "eval_cost": "1.53",
            "prefix_cost": "17.48",
            "data_read_per_join": "24K"
          },
          "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": 15,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "3.82",
            "eval_cost": "1.53",
            "prefix_cost": "22.83",
            "data_read_per_join": "23K"
          },
          "used_columns": [
            "variant_id"
          ]
        }
      },
      {
        "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": 15,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "3.82",
            "eval_cost": "1.55",
            "prefix_cost": "28.20",
            "data_read_per_join": "42K"
          },
          "used_columns": [
            "feature_id",
            "internal_name"
          ]
        }
      },
      {
        "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": 15,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "3.87",
            "eval_cost": "1.55",
            "prefix_cost": "33.61",
            "data_read_per_join": "65K"
          },
          "used_columns": [
            "variant_id",
            "variant"
          ]
        }
      }
    ]
  }
}