The music producer went on an elaborate mission, it seems, to honor a weekend tradition he and 5-year-old Asahd apparently have -- namely, going out to the Golden Arches and securing the kid a Happy Meal.

Sounds like this is a tradition of theirs ... DJK calls is "Happy Meal Saturdays," and Asahd seems more than happy to tag along. Plus, just great father-son bonding right here.

Anyway, fast-forward to the hunt ... which was way harder than Khaled imagined. He filmed himself pulling up to a McDonald's that actually served Happy Meals ... telling both the drive-thru window workers (and his fans) that they'd struck out at 5 other locations.

He says this McDonald's was still serving Happy Meals ... and you can tell the staff was stoked to oblige, getting selfies with Khaled and asking him to drop some of his lines, which he happily did.

While Papa Bear was grateful to have gotten what he needed for his boy -- he was flabbergasted at how hard it was to come across a Happy Meal ... but there's a reason.

Word is ... McDonald's is phasing out current iterations of their staple menu item to replace the not-so-environmentally friendly plastic toys with biodegradable ones ... all in an effort to be more eco-conscious. So, it sounds like Happy Meals might be on pause at the moment.