Yes for sure! In the store in the INSIDE LAAX app you choose your ticket category and the date for which you want to book. Below you will find the field "Guests". Click into it and create a new guest. Fill in the information briefly. In the field Keycard, select "I don't have a keycard". Now you can select other products and complete your booking with the payment.
You can find detailed instructions on how to buy tickets here
You can easily pick up the ordered tickets at the pick-up stations. They are located at all valley stations in Flims, Laax and Falera as well as at Lake Cauma and are marked. Simply scan the QR code from your booking confirmation at the machine and you will receive your booked tickets on a keycard. Long queues at the ticket office are a thing of the past!