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 (
    185415, 185391, 185376, 185375, 185380, 
    185377, 185395, 185385, 185416, 185379, 
    185392, 185393, 185386, 185422, 185378, 
    185402, 185388, 185383, 185425, 185382, 
    185400, 185394, 185403, 185387, 185381, 
    185409, 185419, 185397, 185384, 185413, 
    185429, 185424, 185411, 185423, 185421, 
    185404, 185398, 185399, 185407, 185412, 
    185405, 185414, 185418, 185396, 185427, 
    185417, 185428, 185406, 185408, 185431, 
    185389, 185390, 185401, 185426, 185432, 
    185420, 185430, 185410
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00167

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "81.31"
    },
    "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": 58,
      "rows_produced_per_join": 58,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "69.71",
        "eval_cost": "11.60",
        "prefix_cost": "81.31",
        "data_read_per_join": "396K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (185415,185391,185376,185375,185380,185377,185395,185385,185416,185379,185392,185393,185386,185422,185378,185402,185388,185383,185425,185382,185400,185394,185403,185387,185381,185409,185419,185397,185384,185413,185429,185424,185411,185423,185421,185404,185398,185399,185407,185412,185405,185414,185418,185396,185427,185417,185428,185406,185408,185431,185389,185390,185401,185426,185432,185420,185430,185410)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}