There are actually several websites specializing in replacement keys for laptops. Here's one that specifically lists your keyboard for replacement parts; they should have what you're looking for.
[link|https://laptopkey.com/logitech-illuminated-living-room-wireless-keyboard-k830-laptop-keyboard-keys/|Logitech Illuminated Living-Room Wireless Keyboard K830 Laptop Keyboard Keys|new_window=true]