From Xojo Documentation
The timeout value (in seconds) to be used when connecting to the database. The default is 0, which will use the ODBC driver value.
The timeout value is set before actually connecting to the database. The property can be read, but the value that was previously set will be returned. The value is not returned from the driver. To get the actual value from the driver, use the GetConnectionAttribute method with the ODBCConstant.SQL_LOGIN_TIMEOUT parameter.
Set the timeout to 60 seconds:
db.Timeout = 60