For a quick farm you need to complete the game, because this boost is on the last mission
You need to run on the last difficulty level (Ultimate Badass), which brings 2850 xp for one run
The last rank of Marine requires 234000 xp, which means that from rank 0 to 60 requires 83 runs of 5 minutes each (there are unskippable cutscenes that stretch out the run time)

When we are given control of the character, run to the container that stands in front of the cargo catapult
Waiting for the Queen to appear. IMPORTANT: for her to react to you correctly, you need to stand exactly IN the container, not behind it
When the Queen starts waving her hand at the container (animation to grab), quickly exit the container from behind and run around the RIGHT side of the container to the platform switch (the Queen will be busy with her animation, so she won't bother us)
After activating the switch, stand on the platform, which has started its movement. If done quickly, the Queen will still be in her animation
As the platform rides, move across the platform towards the next switch (careful not to get burned by the fire next to it)
When we activate the next switch, wait for the Queen to move towards us
Move near the platform until she starts to go around the platform on the right
The Queen can't step on this platform on the move, so she'll need to get around this platform. While she is bypassing, run across the platform to the next switch and activate it (the Queen will be shocked by our performance, and will forget to step on us right away)
When she does start moving in our direction, the moving platform will flip it away (game engine tricks)
This will give us time to run to the container that is to the left of the catapult launch button
Again we wait for the Queen and her grabbing animation (I remind you to stand in the container), and then run along the left side of the perimeter to the last switchback
If you get there quickly, the Queen will still be in her animation
Immediately after the switch, run in the opposite direction to the catapult launch button, and wait for the Queen, who should approach us from the other side of the platform
Press the button, and enjoy your 2850 xp