To access MySQL service from your local SQL client, you need to bind your IP for the MySQL service you want to access.You can run the below command to bind IP to your service using app42 command line client.
It will ask you the service name which you want to access (in this case your MySQL service name) and the IP address where you want to access the service from. You will get a public IP as a result which you can use to access the service from your local MySQL client. (Other credentials like username, password & port will remain same as you are using in your app).
You can also refer to the below blog for detailed instructions.