If you want even more speed for Lua, Lua's new experimental sister language, Pallene is really exciting.
Pallene is Lua with strong types, designed for the purpose of being able to (AOT) generate faster and native code.
It's compiler design also has deep knowledge of the Lua implementation, so it short circuits the formal Lua/C API so crossing the Lua/C language boundary in Pallene is even faster (and Lua's is already good...much less overhead than crossing in Python).