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 (
    90739, 91110, 91111, 91196, 91197, 91251, 
    91252, 85285, 85286, 85382, 85383, 
    85433, 85434, 85484, 85485, 83182, 
    83183, 83187, 83188, 86628, 86697, 
    82591, 83354, 85331, 85332, 91141, 
    91142, 86629, 86698, 83180, 83181, 
    83185, 83186, 82823, 82825, 82896, 
    82898, 82969, 82971, 86613, 86614, 
    86682, 86683, 82820, 82893, 82966, 
    83191, 83192
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00093

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 (90739,91110,91111,91196,91197,91251,91252,85285,85286,85382,85383,85433,85434,85484,85485,83182,83183,83187,83188,86628,86697,82591,83354,85331,85332,91141,91142,86629,86698,83180,83181,83185,83186,82823,82825,82896,82898,82969,82971,86613,86614,86682,86683,82820,82893,82966,83191,83192)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}