SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b16f41f3f1dbf840168edc9a05ac1d55dd439b4f45c5540b449455ecf3c8624d' 
  AND token = 'druiNZeejyQMEpAQkux/i2HueCf3CEa3NNisJsd3sjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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