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 (
    91164, 91165, 85300, 85301, 85397, 85398, 
    85448, 85449, 85499, 85500, 85281, 
    85378, 85429, 85480, 85131, 85132, 
    85369, 86652, 86653, 86721, 86722, 
    85291, 85292, 85388, 85389, 85439, 
    85440, 85490, 85491, 86466, 86742, 
    83580, 89796, 89797, 89848, 89849, 
    89920, 89921, 91487, 91488, 85346, 
    85347, 90013, 85068, 85154, 85200, 
    85246, 86513
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00141

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 (91164,91165,85300,85301,85397,85398,85448,85449,85499,85500,85281,85378,85429,85480,85131,85132,85369,86652,86653,86721,86722,85291,85292,85388,85389,85439,85440,85490,85491,86466,86742,83580,89796,89797,89848,89849,89920,89921,91487,91488,85346,85347,90013,85068,85154,85200,85246,86513)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}