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 (
    91414, 91416, 91418, 85102, 85104, 91009, 
    91021, 91033, 91046, 89062, 89495, 
    89496, 89503, 89504, 89511, 89512, 
    89519, 89520, 82833, 82835, 82906, 
    82908, 82979, 82981, 83393, 83395, 
    83403, 83405, 84533, 84534, 84599, 
    84600, 84306, 84307, 89807, 89809, 
    89859, 89861, 89931, 89933, 91497, 
    91499, 85295, 85297, 85392, 85394, 
    85443, 85445
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00108

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 (91414,91416,91418,85102,85104,91009,91021,91033,91046,89062,89495,89496,89503,89504,89511,89512,89519,89520,82833,82835,82906,82908,82979,82981,83393,83395,83403,83405,84533,84534,84599,84600,84306,84307,89807,89809,89859,89861,89931,89933,91497,91499,85295,85297,85392,85394,85443,85445)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}