Rather than a product, think of SAS Viya as foundational technology that enables SAS products like SAS Visual Data Mining and Machine Learning, SAS Visual Analytics, and SAS Data Preparation to leverage advanced in-memory distributed analytics and data management processing. Products based on SAS Viya include other benefits like the ability to program in open source languages, high availability, and improved cloud deployment.
So you don't license SAS Viya as a product, but rather you license products which leverage SAS Viya technology as part of the supporting SAS Platform. You can get more information about SAS Viya here.