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 (
    84610, 84324, 84325, 84497, 84498, 84563, 
    84564, 89049, 89050, 84649, 84650, 
    84345, 84346, 84327, 84328, 84517, 
    84518, 84583, 84584, 84648, 84644, 
    84516, 84582, 84512, 84578, 84626, 
    89039, 84299, 84300, 84319, 84320, 
    84494, 84560, 84314, 84668, 84669, 
    84673, 84674, 84656, 84318, 84536, 
    84537, 84602, 84603, 89035, 84492, 
    84296, 84541
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00120

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (84610,84324,84325,84497,84498,84563,84564,89049,89050,84649,84650,84345,84346,84327,84328,84517,84518,84583,84584,84648,84644,84516,84582,84512,84578,84626,89039,84299,84300,84319,84320,84494,84560,84314,84668,84669,84673,84674,84656,84318,84536,84537,84602,84603,89035,84492,84296,84541)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}