- Edited
So you can have the server with MySQL using standard web tools. Godot can communicate over HTTP, so you could use PHP, for example, with MySQL. You can also communicate with sockets, but this is low level and not needed. Depending on what you are doing, you can use Godot as the server on a Linux machine. This is useful for multiplayer games. But for straight database access, using HTTP will be the easiest.
https://docs.godotengine.org/en/stable/tutorials/networking/http_request_class.html