The instructions that follow use the semanage binary to manage port context; on RHEL, it's part of the policycoreutils-python-utils package:

yum install -y policycoreutils-python-utils

After installing the semanage binary, you can list ports defined with the mysqld_port_t context using semanage with the port option.

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