Sandbox

SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b455c8dbf6556f4608d6e1306fd95a7fbb1f45da53a21ea58b57541bfeb81394' 
  AND token = 'KzNgKfdu8TrwFHu29UMrIp8XBzk/0cXDMhZMT1ool+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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