Answer:
I am a box that holds keys without locks, yet they can unlock your soul.
I can travel from there to here by disappearing, and here to there by reappearing.
My life can be measured in hours, I serve by being devoured. Thin, I am quick. Fat, I am slow. Wind is my foe.
Fatherless and motherless. Born without sin, roared when it came into the world. And never spoke again.
I have one eye. See near and far. I hold the moments you treasure and the things that make you weep.
Boxers do this for a living and kids do it in the backseat for free