How do I activate Mouse Keys with an apple script or the command line?

I have set up mouse keys to activate when clicking option five times. Unfortunately, it appears that I cannot activate mouse keys with this script

repeat 5 times
	tell application "System Events" to key code 58
end repeat

I also tried defaults write com.apple.universalaccess mouseDriver 1 I have system preferences blocked, so I can't turn on mouse keys by going into system preferences. How can I activate mouse keys using a terminal command or script?