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 (
    355546, 357043, 357500, 349778, 351038, 
    351250, 353379, 354255, 354758, 354759, 
    355893, 357319, 349957, 350035, 351097, 
    352135, 352363, 353093, 353545, 353994, 
    354328, 354621, 354651, 355892, 356595, 
    358301, 358739, 350040, 351122, 352395, 
    353833, 354222, 355221, 358440, 350366, 
    351026, 351343, 351619, 353583, 354259, 
    356199, 358214, 359346, 349810, 350074, 
    352488, 353108, 357367, 357667, 357890, 
    349901, 351288, 356833, 358279, 349876, 
    349978, 350482, 350751, 358665, 349886, 
    350041, 352401, 352511, 352843, 352948, 
    353429, 354871, 356064, 356605, 357225, 
    357819, 359066, 349768, 351605, 354103, 
    354184, 354215, 355620, 355874, 358354, 
    350100, 351189, 351275, 352370, 352392, 
    352478, 353120, 353337, 354520, 355256, 
    355289, 355650, 357081, 359079, 359108, 
    359325, 349895, 354513, 354687, 355008
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00630

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "140.18"
    },
    "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": 100,
      "rows_produced_per_join": 100,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "120.18",
        "eval_cost": "20.00",
        "prefix_cost": "140.18",
        "data_read_per_join": "682K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (355546,357043,357500,349778,351038,351250,353379,354255,354758,354759,355893,357319,349957,350035,351097,352135,352363,353093,353545,353994,354328,354621,354651,355892,356595,358301,358739,350040,351122,352395,353833,354222,355221,358440,350366,351026,351343,351619,353583,354259,356199,358214,359346,349810,350074,352488,353108,357367,357667,357890,349901,351288,356833,358279,349876,349978,350482,350751,358665,349886,350041,352401,352511,352843,352948,353429,354871,356064,356605,357225,357819,359066,349768,351605,354103,354184,354215,355620,355874,358354,350100,351189,351275,352370,352392,352478,353120,353337,354520,355256,355289,355650,357081,359079,359108,359325,349895,354513,354687,355008)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}