I have 3 services running on Kubernetes (front, nodejs server and a mysql database). The first service is of type load Balancer and runs the front-end (angular) of the web app with an external ip address. The second service runs the nodejs server with type ClusterIP and the third service is of type ClusterIP and runs mysql.
Assuming firewall ports are whitelisted for your containers, and especially for your mySQL, you should be able to furnish in your TDP connection profile the necessary connection credentials for your mySQL database.... e..g username, password, database name or host, etc.