What is the fastest but not venomous snake? Is it known which non-venomous snake can attack most quickly? I guess it is a snake that attacks its opponent by bites, and not some kind of constrictor.

The fastest non venomous snake is arguably the Eastern Coachwhip with a top speed of upto 10 mph (reference). If it feels cornered, it will attack with bites but otherwise, it prefers to flee.