SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    99277, 99278, 99279, 99280, 99281, 99324, 
    99325, 99326, 99327, 99328, 99329, 
    99344, 99345, 99422, 99423, 99424, 
    99425, 99426, 99427, 99428, 99429, 
    99430, 99431, 99432, 99433, 99434, 
    99435, 99436, 99437, 99529, 99530, 
    99531, 99532, 99533, 99534, 99535, 
    99536, 99537, 99538, 99539, 99540, 
    99541, 99542, 99543, 99544, 99545, 
    99546, 99547, 99548, 99549, 99550, 
    99551, 99552, 99553, 99554, 99555, 
    99556, 99557, 99574, 99575, 99576, 
    100143, 100161, 100162, 100163, 100164, 
    100165, 100166, 100167, 100168, 100388, 
    100389, 100390, 100391, 100431, 100432, 
    100435, 100436, 100665, 100666, 100667, 
    100668, 100669, 100670, 100671, 100672, 
    100673, 100674, 100675, 100676, 101011, 
    101012, 101013, 101014, 101015, 101016
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00174

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "43.24"
    },
    "table": {
      "table_name": "cscart_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": 96,
      "rows_produced_per_join": 96,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "33.64",
        "eval_cost": "9.60",
        "prefix_cost": "43.24",
        "data_read_per_join": "366K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (99277,99278,99279,99280,99281,99324,99325,99326,99327,99328,99329,99344,99345,99422,99423,99424,99425,99426,99427,99428,99429,99430,99431,99432,99433,99434,99435,99436,99437,99529,99530,99531,99532,99533,99534,99535,99536,99537,99538,99539,99540,99541,99542,99543,99544,99545,99546,99547,99548,99549,99550,99551,99552,99553,99554,99555,99556,99557,99574,99575,99576,100143,100161,100162,100163,100164,100165,100166,100167,100168,100388,100389,100390,100391,100431,100432,100435,100436,100665,100666,100667,100668,100669,100670,100671,100672,100673,100674,100675,100676,101011,101012,101013,101014,101015,101016)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}