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 (
    100205, 100206, 100207, 100208, 100209, 
    100210, 100211, 100217, 100218, 100219, 
    100220, 100221, 100222, 100223, 100224, 
    100225, 100226, 100227, 100228, 100229, 
    100230, 100231, 100232, 100233, 100234, 
    100235, 100236, 100237, 100238, 100239, 
    100240, 100241, 100242, 100243, 100244, 
    100245, 100246, 100247, 100248, 100249, 
    100250, 100251, 100252, 100253, 100254, 
    100255, 100256, 100257
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00121

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.62"
    },
    "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": "16.82",
        "eval_cost": "4.80",
        "prefix_cost": "21.62",
        "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 (100205,100206,100207,100208,100209,100210,100211,100217,100218,100219,100220,100221,100222,100223,100224,100225,100226,100227,100228,100229,100230,100231,100232,100233,100234,100235,100236,100237,100238,100239,100240,100241,100242,100243,100244,100245,100246,100247,100248,100249,100250,100251,100252,100253,100254,100255,100256,100257)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}