SELECT 
  product_descriptions.product_id, 
  product_descriptions.short_description, 
  IF(
    product_descriptions.short_description = '' 
    OR product_descriptions.short_description IS NULL, 
    product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  product_descriptions 
WHERE 
  product_descriptions.product_id IN (
    402392, 402400, 402900, 402910, 402914, 
    402919, 402924, 402949, 403659, 403661, 
    403662, 403664, 403672, 404224, 404229, 
    404232, 404254, 404281, 404997, 405016, 
    405031, 405032, 405542, 405547
  ) 
  AND product_descriptions.lang_code = 'en'

Query time 0.00428

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "19.97"
    },
    "table": {
      "table_name": "product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "11",
      "rows_examined_per_scan": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "17.57",
        "eval_cost": "2.40",
        "prefix_cost": "19.97",
        "data_read_per_join": "122K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`goimagine`.`product_descriptions`.`product_id` in (402392,402400,402900,402910,402914,402919,402924,402949,403659,403661,403662,403664,403672,404224,404229,404232,404254,404281,404997,405016,405031,405032,405542,405547)) and (`goimagine`.`product_descriptions`.`lang_code` = 'en'))"
    }
  }
}