SELECT 
  `c`.`category_id`, 
  `d`.`category`, 
  `d`.`products_count` 
FROM 
  `cscart_categories` AS `c` 
  LEFT JOIN `cscart_category_descriptions` AS `d` ON `c`.`category_id` = `d`.`category_id` 
WHERE 
  `c`.`parent_id` = 294 
  AND `c`.`status` = 'A'

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "3.77"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "c",
          "access_type": "ref",
          "possible_keys": [
            "parent"
          ],
          "key": "parent",
          "used_key_parts": [
            "parent_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 5,
          "rows_produced_per_join": 0,
          "filtered": "10.00",
          "cost_info": {
            "read_cost": "3.09",
            "eval_cost": "0.05",
            "prefix_cost": "3.59",
            "data_read_per_join": "5K"
          },
          "used_columns": [
            "category_id",
            "parent_id",
            "status"
          ],
          "attached_condition": "(`dev2`.`c`.`status` = 'A')"
        }
      },
      {
        "table": {
          "table_name": "d",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "category_id"
          ],
          "key_length": "3",
          "ref": [
            "dev2.c.category_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 0,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.13",
            "eval_cost": "0.05",
            "prefix_cost": "3.77",
            "data_read_per_join": "2K"
          },
          "used_columns": [
            "category_id",
            "category",
            "products_count"
          ]
        }
      }
    ]
  }
}