Locate phone with Find My iPhone without locking it
Yes, sure - so long as the phone can currently find a net connection.

Either from another iPhone, using the Find my iPhone app &amp; entering your own Apple ID, or from the website - https://www.icloud.com/#find 

It will show on the map &amp; give you options to Play Sound - useful if it's somewhere near you, down the back of the sofa, in a coat pocket etc, or more seriously if it's been stolen or lost you can set Lost Mode or Wipe all data.