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There are a couple 3rd party programs that do similar things.. or just get a stand that will put your MBP at an angle so the cat doesn't jump on it..

Lockey

edit: you can also try Keyboard Cleaner

Just tried this on my 2013 MBP with 10.8.5:

The external keyboard still works fine, and I was able to disable, then reenable my internal keyboard.

To disable the internal keyboard of a portable Mac:

sudo kextunload /System/Library/Extensions/AppleUSBTopCase.kext/Contents/PlugIns/AppleUSBTCKeyboard.kext/
The internal keyboard is then disabled, external keyboards will still work.

To re-enable the internal keyboard of a portable Mac:

sudo kextload /System/Library/Extensions/AppleUSBTopCase.kext/Contents/PlugIns/AppleUSBTCKeyboard.kext/

When I initially disable the internal keyboard, terminal notifies me that:

(kernel) Can't unload kext com.apple.driver.AppleUSBTCKeyboard; classes have instances:

(kernel)     Kext com.apple.driver.AppleUSBTCKeyboard class AppleUSBTCKeyboard has 11 instances.

Failed to unload com.apple.driver.AppleUSBTCKeyboard - (libkern/kext) kext is in use or retained (cannot unload).

Nevertheless, the command works, no ill effects.

Thanks to: macrumours

Mouse keys could actually solve your problem without any apps. It's a built-in OS X accessibility option (can be turned on and off). Basically, when you press the Option key 5 times, it's enabled (or disabled in the same way) and then you can only use like 6 to 8 keys on the keyboard to control the mouse - other keys and touchpad are disabled - so if your cat doesn't hit 1 or 2 keys (left and right mouse clicks), you are fine.

It is not 100% solution but could work in 80-90% cases. I am using it when I put my ergonomic keyboard on top of the MacBook Pro keyboard. Wonder when (and if) will ergonomic keyboards come to notebooks, to be honest. Soon, there will be world fulled with blind programmers with RSI or carpal tunnels in their wrists.

My actual version is El Capitan 10.11.1, but I think it worked on 10.10.5 which I had few weeks ago.

You could put a password on your screen saver ("Require password [time] seconds after sleep or screen saver begins" in the "General" tab of the "Security" section of System Preferences, probably best to add a hot corner for quick activation). This will require you to enter your password whenever you return to your computer - unless your cat knows it, you'll be protected from any accidental input.

Unfortunately, this means you have to be not using your computer at that point. Other than using an external monitor and so on and closing the lid, I don't know of any built in way of disabling the keyboard.

Looks like all cats love to mess with MacBooks

This http://www.indiegogo.com/Mac-OS-X-Keyboard-Lock-Application-Lockey Should solve your problem

or try this
http://jan.prima.de/~jan/plok/archives/48-Keyboard-Cleaner.html

PS: Are you the same user who asked this question over here http://discussions.apple.com/thread.jspa?threadID=1646187

Try the free software CatNip, which claims to detect cat-like typing and locks the keyboard in response.

http://macifier.com/
this app is free, locks keyboard, n doesn't shut off screen (you can continue to FaceTime / Skype, or watch a movie)!! Other apps blur the screen.

There's a excellent free app that does exactly that. It's called KeyboardCleanTool, and it's made by the same guy who made BetterSnapTool.

Unlike with Keyboard Cleaner, you can still use your computer as normal while your keyboard is disabled.