A journey into concurrent programming in Scala – a good article about concurrent programming in Scala
Java Executors documentation – Scala uses Javas future system with Executors etc.
Play uses Akka so you can also use Akka dispatchers for the ExecutionContext required in the Controllers.
Link to Hikaricp library that creates connection pools for database access on JVM
Ebooks
Concepts and Technologies for Distributed Systems and Big Data Processing
Philipp Haller
Scala Futures, Async, and Actors