mysqltuner script to optimize my mysql database
You have to decrease max_connections as far as you have only 9 simultaneous connections within 138K for 12 hours (and 600 is defined). Default 151 connections if enough.
You have to increase your key_buffer_size to at least twice big as MYISAM indices (64MB, and 256MB prevents troubles in the future) to fit all the indices into the memory.
You can reduce InnoDB buffer pool to reasonable 2GB instead of 32GB, while only 422MB of data exists.