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 (
    296873, 296839, 296831, 296893, 296928, 
    296832, 296841, 296919, 296881, 296861, 
    296883, 296838, 296848, 296853, 296899, 
    296846, 296833, 296858, 296886, 296894, 
    296835, 296869, 296892, 296837
  ) 
  AND product_descriptions.lang_code = 'en'

Query time 0.00362

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "19.94"
    },
    "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": "17.54",
        "eval_cost": "2.40",
        "prefix_cost": "19.94",
        "data_read_per_join": "122K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`goimagine`.`product_descriptions`.`product_id` in (296873,296839,296831,296893,296928,296832,296841,296919,296881,296861,296883,296838,296848,296853,296899,296846,296833,296858,296886,296894,296835,296869,296892,296837)) and (`goimagine`.`product_descriptions`.`lang_code` = 'en'))"
    }
  }
}