SELECT 
  q_product_descriptions.product_id, 
  q_product_descriptions.short_description, 
  IF(
    q_product_descriptions.short_description = '', 
    q_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  q_product_descriptions 
WHERE 
  q_product_descriptions.product_id IN (
    8395, 8396, 8397, 8398, 8399, 8400, 8401, 
    8402, 8403, 8404, 8405, 8406, 8407, 
    8408, 8409, 8410, 8412, 8414, 8415, 
    8419, 8425, 8426, 8427, 8428, 8429, 
    8430, 8431, 8432, 8435, 8436, 8438, 
    8439
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00081

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "76.81"
    },
    "table": {
      "table_name": "q_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": 32,
      "rows_produced_per_join": 32,
      "filtered": "100.00",
      "index_condition": "((`portal`.`q_product_descriptions`.`product_id` in (8395,8396,8397,8398,8399,8400,8401,8402,8403,8404,8405,8406,8407,8408,8409,8410,8412,8414,8415,8419,8425,8426,8427,8428,8429,8430,8431,8432,8435,8436,8438,8439)) and (`portal`.`q_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "70.41",
        "eval_cost": "6.40",
        "prefix_cost": "76.81",
        "data_read_per_join": "122K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ]
    }
  }
}