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 (
    101257, 101258, 101259, 101260, 101261, 
    101262, 101263, 101264, 101265, 101266, 
    101267, 101268, 101269, 101270, 101271, 
    101272, 101273, 101274, 101275, 101276, 
    101277, 101278, 101279, 101280, 101281, 
    101282, 101283, 101284, 101285, 101286, 
    101287, 101288, 101289, 101290, 101291, 
    101292, 101293, 101294, 101295, 101296, 
    101297, 101298, 101299, 101300, 101301, 
    101302, 101303, 101304
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.62"
    },
    "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": "16.82",
        "eval_cost": "4.80",
        "prefix_cost": "21.62",
        "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 (101257,101258,101259,101260,101261,101262,101263,101264,101265,101266,101267,101268,101269,101270,101271,101272,101273,101274,101275,101276,101277,101278,101279,101280,101281,101282,101283,101284,101285,101286,101287,101288,101289,101290,101291,101292,101293,101294,101295,101296,101297,101298,101299,101300,101301,101302,101303,101304)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}