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 (
    91342, 91348, 91335, 91340, 91332, 91361, 
    91363, 91391, 91393, 91362, 91364, 
    92240, 92245, 92247, 92248, 92249, 
    92250, 92252, 92253, 92485, 92486, 
    92487, 91392, 91394, 91359, 91389, 
    92508, 86828, 91331, 91360, 91357, 
    91387, 92241, 92242, 92243, 92244, 
    92246, 92251, 92483, 92484, 91358, 
    91390, 92488, 91388, 92476, 92477, 
    92478, 92479
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00039

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 (91342,91348,91335,91340,91332,91361,91363,91391,91393,91362,91364,92240,92245,92247,92248,92249,92250,92252,92253,92485,92486,92487,91392,91394,91359,91389,92508,86828,91331,91360,91357,91387,92241,92242,92243,92244,92246,92251,92483,92484,91358,91390,92488,91388,92476,92477,92478,92479)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}