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 (
    87640, 87876, 88506, 88507, 88510, 87987, 
    90828, 87632, 88561, 87637, 90827, 
    87938, 87941, 87997, 88026, 87781, 
    87882, 87988, 88047, 88048, 88050, 
    88051, 88052, 88053, 88054, 87990, 
    87961, 87875, 87937, 87950, 87959, 
    88798, 90826, 87952, 88004, 87998, 
    88000, 87881, 88031, 87948, 88702, 
    88749, 87945, 87942, 87964, 88029, 
    88018, 88021
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00109

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (87640,87876,88506,88507,88510,87987,90828,87632,88561,87637,90827,87938,87941,87997,88026,87781,87882,87988,88047,88048,88050,88051,88052,88053,88054,87990,87961,87875,87937,87950,87959,88798,90826,87952,88004,87998,88000,87881,88031,87948,88702,88749,87945,87942,87964,88029,88018,88021)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}