ccpd = Canon Printer Daemon for CUPS
On a system with Linux MINT 18 (based on Ubuntu 16.4 LTS) and a Canon LBP7210C network printer, I did this for a faster timeout to take precedence.
Edit the override.conf file
$ sudo systemctl edit ccpd.service
to set the timeout to 10 seconds. Save and exit.
This change will prevail between each shutdown.
To check the modified timeout value, run
$ systemctl show ccpd.service -p TimeoutStopUSec TimeoutStopUSec=10s
The same method was used in this post https://askubuntu.com/a/810237 for a different service.
Note: Each service has a timeout and its there for a reason. Changing the timeout for a network printer seems OK. For other services (eg: disk drives) the effect of changing a preset value must be carefully considered.