For Mac users, you can find history files in
/Users/<username>/Library/Application Support/MySQL/Workbench/sql_history
Although there are only a few dates in the history file stored there (it seems that Workbench is using it for some indexing .... not sure though). If you need the actual query history, you can check the log files for
/Users/<username>/Library/Application Support/MySQL/Workbench/log/
source share