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 (
    9741, 9742, 9743, 9744, 9745, 9746, 9747, 
    9748, 9749, 9750, 9751, 9752, 9753, 
    9754, 9755, 9756, 9757, 9758, 9759, 
    9760, 9761, 9762, 9763, 9764, 9765, 
    9766, 9767, 9768, 9769, 9770, 9771, 
    9772
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00078

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 (9741,9742,9743,9744,9745,9746,9747,9748,9749,9750,9751,9752,9753,9754,9755,9756,9757,9758,9759,9760,9761,9762,9763,9764,9765,9766,9767,9768,9769,9770,9771,9772)) 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"
      ]
    }
  }
}