Looks like Mysql 5.7 supports async executions wit...

# exposed

[tapac]

Looks like Mysql 5.7 supports async executions with enabled X-Plugin and even has related API (https://dev.mysql.com/doc/dev/connector-j/com/mysql/cj/api/x/Statement.html#executeAsync--) in latest jdbc connectors (development release).
Node.js examples https://www.percona.com/blog/2016/05/27/asynchronous-query-execution-mysql-5-7-x-plugin/