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 (
    86225, 89975, 91977, 91979, 91980, 91982, 
    91983, 82556, 84117, 85583, 89595, 
    89596, 89597, 82335, 82336, 82401, 
    82409, 82419, 83138, 82405, 82411, 
    82425, 90123, 91992, 91936, 89202, 
    91970, 91973, 86234, 82374
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00074

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (86225,89975,91977,91979,91980,91982,91983,82556,84117,85583,89595,89596,89597,82335,82336,82401,82409,82419,83138,82405,82411,82425,90123,91992,91936,89202,91970,91973,86234,82374)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}