The default TCP port for mysqld is 3306; and the SELinux context type used is mysqld_port_t.

If you configure mysqld to use a different TCP port, you may need to set the context for the new port. For example to define the SELinux context for a non-default port such as port 3307:

semanage port -a -t mysqld_port_t -p tcp 3307

To confirm that the port is added:

$> semanage port -l | grep mysqld
mysqld_port_t                  tcp      3307, 1186, 3306, 63132-63164