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 (
    100258, 100259, 100260, 100261, 100262, 
    100263, 100264, 100265, 100266, 100267, 
    100268, 100269, 100270, 100271, 100272, 
    100273, 100274, 100275, 100276, 100277, 
    100278, 100279, 100280, 100281, 100282, 
    100283, 100284, 100285, 100286, 100287, 
    100288, 100289, 100290, 100291, 100296, 
    100297, 100298, 100299, 100300, 100301, 
    100302, 100303, 100304, 100305, 100306, 
    100307, 100308, 100309, 100310, 100311, 
    100312, 100313, 100314, 100315, 100316, 
    100317, 100318, 100319, 100320, 100327, 
    100328, 100329, 100330, 100331, 100332, 
    100333, 100334, 100335, 100336, 100337, 
    100338, 100339, 100340, 100341, 100342, 
    100343, 100344, 100345, 100346, 100347, 
    100348, 100349, 100350, 100351, 100352, 
    100353, 100354, 100355, 100356, 100357, 
    100359, 100360, 100438, 100439, 100440, 
    100441
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00166

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 (100258,100259,100260,100261,100262,100263,100264,100265,100266,100267,100268,100269,100270,100271,100272,100273,100274,100275,100276,100277,100278,100279,100280,100281,100282,100283,100284,100285,100286,100287,100288,100289,100290,100291,100296,100297,100298,100299,100300,100301,100302,100303,100304,100305,100306,100307,100308,100309,100310,100311,100312,100313,100314,100315,100316,100317,100318,100319,100320,100327,100328,100329,100330,100331,100332,100333,100334,100335,100336,100337,100338,100339,100340,100341,100342,100343,100344,100345,100346,100347,100348,100349,100350,100351,100352,100353,100354,100355,100356,100357,100359,100360,100438,100439,100440,100441)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}