SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    89347, 89346, 89255, 89348, 89261, 89260, 
    89256, 89259, 89258, 94694, 94695, 
    94698, 94699, 94700, 94701, 94702, 
    96299, 96300, 96301, 96749, 96789, 
    96790, 97818, 97819, 97822, 97823, 
    97824, 97825, 97826, 98266, 98267, 
    98268, 98269, 98270, 98271, 98272, 
    98273
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00078

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "16.67"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 37,
      "rows_produced_per_join": 37,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "12.97",
        "eval_cost": "3.70",
        "prefix_cost": "16.67",
        "data_read_per_join": "141K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (89347,89346,89255,89348,89261,89260,89256,89259,89258,94694,94695,94698,94699,94700,94701,94702,96299,96300,96301,96749,96789,96790,97818,97819,97822,97823,97824,97825,97826,98266,98267,98268,98269,98270,98271,98272,98273)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}