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 (
    296901, 296878, 296871, 296867, 296879, 
    296918, 296870, 296855, 296866, 296896, 
    296812, 296824, 296915, 296865, 296898, 
    296877, 296907, 296920, 296889, 296921, 
    296926, 296849, 296814, 296859
  ) 
  AND product_descriptions.lang_code = 'en'

Query time 0.00206

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "20.21"
    },
    "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": "17.81",
        "eval_cost": "2.40",
        "prefix_cost": "20.21",
        "data_read_per_join": "122K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`goimagine`.`product_descriptions`.`product_id` in (296901,296878,296871,296867,296879,296918,296870,296855,296866,296896,296812,296824,296915,296865,296898,296877,296907,296920,296889,296921,296926,296849,296814,296859)) and (`goimagine`.`product_descriptions`.`lang_code` = 'en'))"
    }
  }
}