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 (
    355717, 355719, 356949, 358285, 358290, 
    358547, 358637, 351318, 352445, 352554, 
    353615, 357398, 358938, 350865, 352707, 
    353944, 354062, 357493, 358027, 358350, 
    350352, 352393, 352805, 354936, 355415, 
    357144, 357692, 358163, 358224, 359190, 
    350377, 351703, 353963, 354795, 355367, 
    358009, 358236, 350361, 354865, 358187, 
    351113, 353951, 354808, 354933, 354973, 
    356749, 357418, 358037, 358280, 351114, 
    351447, 353723, 354415, 354767, 355148, 
    355850, 357340, 359225, 359323, 351107, 
    352583, 353870, 354344, 355656, 356593, 
    357219, 358204, 351183, 352386, 353768, 
    354431, 354916, 355645, 356046, 356661, 
    356846, 359324, 359395, 359418, 352382, 
    350862, 350908, 350989, 352231, 353614, 
    355142, 356901, 357522, 357567, 357955, 
    358789, 351261, 353825, 354743, 355304, 
    355525, 355919, 356826, 357569, 357956
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00433

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 (355717,355719,356949,358285,358290,358547,358637,351318,352445,352554,353615,357398,358938,350865,352707,353944,354062,357493,358027,358350,350352,352393,352805,354936,355415,357144,357692,358163,358224,359190,350377,351703,353963,354795,355367,358009,358236,350361,354865,358187,351113,353951,354808,354933,354973,356749,357418,358037,358280,351114,351447,353723,354415,354767,355148,355850,357340,359225,359323,351107,352583,353870,354344,355656,356593,357219,358204,351183,352386,353768,354431,354916,355645,356046,356661,356846,359324,359395,359418,352382,350862,350908,350989,352231,353614,355142,356901,357522,357567,357955,358789,351261,353825,354743,355304,355525,355919,356826,357569,357956)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}