Problem

• Given, a KPS table is defined with a secondary key or combo key via 'Use the following property name(s) for looking up table from a selector'.
• Then, selector syntax lookups on such keys works, ex: ${kps.yourTable[secondayKey].value}
• But, once such selector syntax enabled key(s) are defined, how can you lookup values via the table's primary key?
• Can primary key lookup then be done from selector syntax, or from policy filters at all?

Resolution

You cannot use selector syntax for a primary key lookup once a KPS table is defined with secondary(s), however you can still do it from policy via the KPS scripting API in a scripting filter, as that uses the primary key. link

Also, the KPS REST API has one or more GET methods that can do it. link