sudo /usr/libexec/plistbuddy -c "Add:tokenRemovalAction integer 1" /Users/<username>/Library/Preferences/com.apple.screensaver.plist
sudo /usr/libexec/plistbuddy -c "Add:askForPassword integer 1" /Users/<username>/Library/Preferences/com.apple.screensaver.plist
sudo /usr/libexec/plistbuddy -c "Add:askForPasswordDelay integer 0" /Users/<username>/Library/Preferences/com.apple.screensaver.plist
You can also READ what the settings are using ‘defaults':
$ sudo defaults read /Users/<username>/Library/Preferences/com.apple.screensaver