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 (
    82420, 82354, 82421, 82381, 89334, 89336, 
    82355, 82380, 89333, 86823, 89335, 
    89370, 89372, 89273, 89276, 89369, 
    89371, 89374, 86819, 86821, 89272, 
    89275, 89271, 89274, 86822, 89327, 
    89373, 89266, 89328, 89329, 89269, 
    89331, 89265, 89330, 89264, 86817, 
    89368, 89268, 89367, 89308, 89267, 
    86818, 86820, 89332, 89309, 89321, 
    89323, 89322
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00099

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 (82420,82354,82421,82381,89334,89336,82355,82380,89333,86823,89335,89370,89372,89273,89276,89369,89371,89374,86819,86821,89272,89275,89271,89274,86822,89327,89373,89266,89328,89329,89269,89331,89265,89330,89264,86817,89368,89268,89367,89308,89267,86818,86820,89332,89309,89321,89323,89322)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}