SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4246fdfac19afb9639d9730a79d9bfc7f5a4c868615c0fe64ae762466f1fc378' 
  AND token = '1oJ8skUQmAb6tclSf7yNwpPa3sbo9Mu4nUVIoIZdpKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}