secure way to connect with remote Mysql database
What are the clients?  PHP?  Java?  (etc, etc)  There are potentially serious hacks that can do things like "SQL Injection" through them.  That is perhaps more common than IP restrictions.

Do you have root only from some secure place?  Does it have a hardened password?

Are all the application 'users' granted access only to the desired database, and with only the desired permissions?  And are all the passwords hardened?

Where are the client passwords?  Visible in code?  That is, if a hacker can get to the code, are the passwords a useless defense?

SSL is only one issue.  If your provider does not allow for SSL, see if someone else does.  If not, then consider hosting the servers yourself; it's cheaper in the long run, but much more work.  And it would solve the IP problem.

Check skip_name_resolve.