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 (
    35664, 35665, 35666, 35667, 35668, 35669, 
    35670, 35671, 35672, 35673, 35674, 
    35675, 35676, 35677, 35678, 35679, 
    35680, 35681, 35682, 35683, 35684, 
    35685, 35686, 35687, 35688, 35689, 
    35690, 35691, 35692, 35693, 35694, 
    35695
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00073

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 (35664,35665,35666,35667,35668,35669,35670,35671,35672,35673,35674,35675,35676,35677,35678,35679,35680,35681,35682,35683,35684,35685,35686,35687,35688,35689,35690,35691,35692,35693,35694,35695)) 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"
      ]
    }
  }
}