I know that query execution plan visualizer exists.
But never see it for mysql. Do you know one?
I know this is an old question, but if you're using MySQL workbench, have a look at their tools: https://www.mysql.com/products/workbench/performance/
The explain plan shows the operations MySQL performs when it runs SQL statements. This information can help optimize SQL performance. MySQLWorkbench Visualize Explain plans graphically show and highlight how SQL statements execute within MySQL.
In my version (6.3 on a mac), it's the Query option from the top menu, then "Explain current statement" - use this on the actual query, not the EXPLAIN ...
query.
See also https://opensourcedba.wordpress.com/2012/11/09/visual-explain-part-2/
Hope that helps (: