Sliding glass door lock and handle

Thanks for posting. This looks just like our 82-086 Keyed Handle Set to me. Let me know if you have further questions. 

Do you mean the outside key lock, or the mortise lock in the door the handle set interfaces with? If it's the outside key lock, and the handle set is otherwise undamaged, you likely can replace the key cylinder with our 82-310. This blog article here goes into detail as to how to do this. 

If it's the mortise lock in the door, we'd need a picture of it to identify which one you have (a few different versions work with this handle set). To ensure the mortise lock is the issue, try manually throwing the lock with a slotted screwdriver. If it doesn't budge, then you know it needs to be replaced.