I'm the author of a schema management tool, Skeema [1], designed to solve this problem for MySQL and MariaDB.
There are a number of other existing tools that can compare/diff schemas on 2 live databases, but Skeema is designed to also actually manage your database structure through a declarative repo of CREATE statements. It works at any scale (natively supports sharding and external OSC tools) and is trusted by several large users, including GitHub [2] and Twilio SendGrid [3].