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 (
    89938, 91504, 82840, 82913, 82986, 83400, 
    83410, 85302, 85399, 85450, 85501, 
    89759, 85348, 86655, 86656, 86724, 
    86725, 86516, 86792, 83293, 83300, 
    86486, 86487, 86762, 86763, 82619, 
    82620, 83422, 83423, 89762, 85093, 
    85179, 85225, 85271, 83221, 83226, 
    85327, 85424, 85475, 85526, 82847, 
    82848, 82920, 82921, 82993, 82994, 
    83477, 83478
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00071

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 (89938,91504,82840,82913,82986,83400,83410,85302,85399,85450,85501,89759,85348,86655,86656,86724,86725,86516,86792,83293,83300,86486,86487,86762,86763,82619,82620,83422,83423,89762,85093,85179,85225,85271,83221,83226,85327,85424,85475,85526,82847,82848,82920,82921,82993,82994,83477,83478)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}