Servers are located in Ohio [NA] and Frankfurt [EU].

Playtest times are separated servers. This means that if you log in to the game when EU playtest times are active, you will be automatically connected to the server in Frankfurt which will explain the sudden change in latency. If you are from NA, play during NA active playtest times for the best playing experience.

This also means that you are currently unable to select a server (well unless you log in during the time each server is active). The servers (and latency) you see in-game are not game servers, just login servers. They are completely separate from game servers and only game server latency will be relevant to your gameplay and connection.