Production rules systems in the 1970s (when they were in vogue for "expert systems") did not use indexes and generally had poor execution performance compared to modern "business rules" engine.
Production rules are related to other logic-based methods of programming such as "logic programming" (which tends to progress backwards from a desired consequence to prove it is satisfied) or "theorem provers" that could demonstrate that a section of code satisfies certain invariants.
Real business rules engines use something like
https://en.wikipedia.org/wiki/Rete_algorithm
Production rules systems in the 1970s (when they were in vogue for "expert systems") did not use indexes and generally had poor execution performance compared to modern "business rules" engine.
Production rules are related to other logic-based methods of programming such as "logic programming" (which tends to progress backwards from a desired consequence to prove it is satisfied) or "theorem provers" that could demonstrate that a section of code satisfies certain invariants.