Ok something that worked for me to at least restore most of the history
Go to *\AppData\Roaming\Maxthon5\Users\*USERNAME*\History
There you have history.dat which is the current history file and other files: History_Part_xx.dat
This are saved history files. Rename or delete the current History.dat (renaming i safer), and rename the last History_Part_xx.dat to History.dat
Maxthon should be closed while doing this, when you open Maxthon again you should have access to the cutoff date from the last file, mine was from the 17.09.2017, so I only lost about a week of history, but its searchable again.