Oxxo has nothing to do with it. At the LAST traffic light heading west, turn right and next corner right, and at virtually on the next corner, glance corner at your right, and you will see it. Yip parking is not too handy.
Best trick in US is to tell the person supervising self check the machine won'tl take MX card. They will lead you to pickup and pay area, check you out and no lines! Has worked multiple times!