This is just one recent example: https://www.infoq.com/articles/api-gateway-clojure-golang
The money quote:
"The end result enabled us to reduce 25 instances (c4 xlarge) running Clojure code - able to process 60 concurrent requests, to two instances (c3.2xlarge) running Go code able to support ~5000 concurrent requests a minute"
If you google around you'll find more stories like that.
To do better than Go you would have to drop to C++ or Rust.