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 (
    36672, 36758, 57792, 36754, 36692, 150992, 
    54764, 36683, 49009, 36870, 36707, 
    61058, 36687, 36716, 61982, 36827, 
    36704, 36677, 77482, 36755, 36664, 
    36688, 36798, 36690, 36680, 47619, 
    36665, 36732, 36773, 36669, 36739, 
    36822, 36765, 76558, 36679, 36691, 
    54762, 36678, 36844, 36702, 36756, 
    36768, 36714, 61979, 36772, 36823, 
    36731, 36807
  ) 
  AND product_descriptions.lang_code = 'en'

Query time 0.00181

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "40.35"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "35.55",
        "eval_cost": "4.80",
        "prefix_cost": "40.35",
        "data_read_per_join": "244K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`goimagine`.`product_descriptions`.`product_id` in (36672,36758,57792,36754,36692,150992,54764,36683,49009,36870,36707,61058,36687,36716,61982,36827,36704,36677,77482,36755,36664,36688,36798,36690,36680,47619,36665,36732,36773,36669,36739,36822,36765,76558,36679,36691,54762,36678,36844,36702,36756,36768,36714,61979,36772,36823,36731,36807)) and (`goimagine`.`product_descriptions`.`lang_code` = 'en'))"
    }
  }
}