With the help of a launch daemon you can clear this folder each time you reboot your computer.
Create a file in your home directory called local.rm.coresymbolicationd.plist using the editor of your choice with the following contents:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/...
Sadly I don't think you can invoke this behavior and this is not the solution you are asking for, though as I imagine you are using a keyboard (apple?) you could always use the hotkeys to lock your laptop and screen.
Option–Command–Power / Option–Command–Media Eject: Put Mac to
Control–Shift–Power / Control–Shift–Media Eject : Put
display(s) to sleep
There is nothing in the one-liner which limits by days. If you want to see all visited pages, remove the trailing \ | head -n 30 (which currently cuts off the output after 30 lines).
If you still don't see more than two days, check the history settings in Safari.