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 (
    89403, 89331, 82403, 82410, 82424, 89265, 
    89330, 89264, 86817, 89368, 89268, 
    89367, 89308, 91920, 91928, 89267, 
    86818, 86820, 89591, 89592, 86226, 
    89295, 86237, 89332, 89294, 89405, 
    91912, 89309, 89321, 86230, 89257, 
    89323, 91993, 91994, 91995, 91996, 
    91997, 91998, 91999, 89322, 89325, 
    86816, 89306, 89324, 89366, 89305, 
    89317, 82385
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00065

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 (89403,89331,82403,82410,82424,89265,89330,89264,86817,89368,89268,89367,89308,91920,91928,89267,86818,86820,89591,89592,86226,89295,86237,89332,89294,89405,91912,89309,89321,86230,89257,89323,91993,91994,91995,91996,91997,91998,91999,89322,89325,86816,89306,89324,89366,89305,89317,82385)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}