Changing data source on Access front end
You can convert your physical tables in the Access database to the linked tables. The linked table is just this: a link. The actual data is located elsewhere. For this to work you will need to create a connection to the MySQL database supported by Access. Access supports OLEDB and ODBC connections. Download a MySQL OLEDB or ODBC driver, create a DSN (if you chose the ODBC path). Open your Access database and click on the External Data toolbar. Select "Create Link" and then create links to all your data that you have exported to MySQL. The linked tables will be created alongside your existing tables. You can then try deleting the physical tables one-by-one and renaming the matching linked tables, so that the names are the same. You can test the application step-by-steps after each table.

BTW, you could use Access to export data via the driver as well. It would export it together with the indices