3 Volt Active Low Relay
You haven't just got a relay. You have a relay module.



Figure 1. Relay module with switching transistor highlighted.

The transistor highlighted in the image is what switches the relatively high relay coil current by the relatively small control signal on the IN pin.


  Does the 3V 3.3V Relay description only refer to the coil voltage and is it ok to toggle it via a Digital Out pin without additional resistors?


The Vcc pin should be powered from 3.3 V. The input should be driven by a 3.3 V logic signal. It may tolerate a 5 V logic signal but without a datasheet we can't say for sure.



See Michael Karas' answer to Control 5v relay through 3.3v GPIO using NPN transistor where he has drawn the likely schematics.