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 (
    86227, 84122, 82447, 89402, 89404, 91284, 
    89403, 89331, 82403, 82410, 82424, 
    89265, 89330, 89264, 86817, 89368, 
    89268, 89367, 89308, 91920, 91928, 
    89267, 86818, 86820, 89591, 89592, 
    86226, 89295, 86237, 89332
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00075

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 (86227,84122,82447,89402,89404,91284,89403,89331,82403,82410,82424,89265,89330,89264,86817,89368,89268,89367,89308,91920,91928,89267,86818,86820,89591,89592,86226,89295,86237,89332)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}