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 (391685, 391682) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "2.81"
    },
    "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": 2,
      "rows_produced_per_join": 2,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "2.41",
        "eval_cost": "0.40",
        "prefix_cost": "2.81",
        "data_read_per_join": "13K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (391685,391682)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
391682 <p>Funeral Agency Genti Fier trhas been operating professionally for several years in the city of Fier and in every corner of Albania and Italy. Thanks to an experience and a tradition rooted in time, the company represents a guarantee in funeral services, offering accurate and measured in all circumstances. With courtesy and availability we help our clients in a painful moment such as bereavement, providing support and support in the moment that naturally follows the serious loss of a loved one. You can rely on us for the various funeral services, we will assist you with the usual professionalism and discretion, and we will do our best to relieve you of any further worries at what is already a difficult time. For more information or in case of mourning, you can contact us at any time: our staff will be at your disposal providing all the necessary support.</p>
391685 <p>Funeral Agency Genti Fier has been operating professionally for several years in the city of Fier and in every corner of Albania and Italy. Thanks to an experience and a tradition rooted in time, the company represents a guarantee in funeral services, offering accurate and measured in all circumstances. With courtesy and availability we help our clients in a painful moment such as bereavement, providing support and support in the moment that naturally follows the serious loss of a loved one. You can rely on us for the various funeral services, we will assist you with the usual professionalism and discretion, and we will do our best to relieve you of any further worries at what is already a difficult time. For more information or in case of mourning, you can contact us at any time: our staff will be at your disposal providing all the necessary support.</p>