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 (
    6415, 6416, 6417, 6418, 6419, 6420, 6421, 
    6422, 6423, 6424, 6425, 6426, 6427, 
    6428, 6429, 6430, 6431, 6432, 6433, 
    6434, 6435, 6436, 6437, 6438, 6439, 
    6440, 6441, 6442, 6443, 6444, 6445, 
    6446, 6447, 6448, 6449, 6450, 6451, 
    6452, 6453, 6454, 6456, 6457, 6458, 
    6459, 6460, 6461, 6462, 6463, 6464, 
    6465, 6466, 6467, 6468, 6469, 6470, 
    6471, 6472, 6473, 6474, 6475, 6476, 
    6477, 6478, 6479
  ) 
  AND q_product_descriptions.lang_code = 'en'

Query time 0.00099

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "153.61"
    },
    "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": 64,
      "rows_produced_per_join": 64,
      "filtered": "100.00",
      "index_condition": "((`portal`.`q_product_descriptions`.`product_id` in (6415,6416,6417,6418,6419,6420,6421,6422,6423,6424,6425,6426,6427,6428,6429,6430,6431,6432,6433,6434,6435,6436,6437,6438,6439,6440,6441,6442,6443,6444,6445,6446,6447,6448,6449,6450,6451,6452,6453,6454,6456,6457,6458,6459,6460,6461,6462,6463,6464,6465,6466,6467,6468,6469,6470,6471,6472,6473,6474,6475,6476,6477,6478,6479)) and (`portal`.`q_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "140.81",
        "eval_cost": "12.80",
        "prefix_cost": "153.61",
        "data_read_per_join": "244K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ]
    }
  }
}