SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '673c61b53c49f2c87d02c0bfec767d89455a89f2d825db2bc166cc0c5c344f7c' 
  AND token = 'lzXdnQr8osSXlGRiB5358cdTvkDcHHN795Uslf902cU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}