I've had painful wee hour sleeping spasms like that, anywhere in the lower extremities from the thighs and hamstrings down to the arches of my feet. Like, falling out of bed rolling on the floor with the cats looking at me like I'm the crazy one when they're the ones who poop in a box, wear fur in summer and sniff each others butts.
But I digress.
Anyway, after decades of body aches and pains, from sudden spasms to chronic joint and muscle pain, I've read all the credible literature I could find in medical and science journals.
Summary: Nobody knows for certain what causes muscle spasms or how to prevent or fix them. It varies for everyone.
Some of my muscle spasms, especially in the neck and shoulder, are due to old injuries with permanent damage. My C1-C2 are permanently damaged, putting more strain on the muscles to support my noggin. Then more recent injury added a shoulder break and separation along with aggravating the neck injury. And the combination of injuries led to injury-induced scoliosis, a wrong-way curvature of the spine due to muscle imbalance and hip tilt. That in turn can lead to problems pedaling and running due to changes in effective leg length.
That pretty much limits my bike rides to an hour or so continuous riding. On a really good day I might last 90-120 minutes of continuous riding before the spasms start. The other night it was only an hour so I cut that ride short. I can handle longer rides with enough rest breaks to stretch and work out the kinks. I do physical therapy. I tweak my bike fit whenever necessary and have a variety of bikes to choose appropriately to suit my neck, shoulder, etc., on any given day. But it is what it is.
But the arch cramps are unrelated to anything. It has nothing to do with hydration, diet, exercise, injury, etc. I've had 'em since I was a kid and still get those cramps occasionally. Sometimes just the weight of a blanket the wrong way on my toe provokes the spasms. Some days I can jog up to 10 miles without foot pain. Other days just walking to the bathroom causes those arch spasms. So I have about six pairs of running shoes and another three or four pairs of walking shoes, so I have a variety of fits to choose from to suit my feet. And I often supplement or replace the original insoles, usually with ProFoot Miracle insoles (best I've found by far, and I've tried many since I was a kid and needed custom orthotics).
I've mentioned before on the topic that boxer Manny Pacquiao has reported occasional problems with painful spasms, mostly in his calves. He could afford not only the finest medical care available, but could probably single-bank-accountedly fund an entire research project into the topic. But even he hasn't found a reliable cure or preventive.
Besides hydration, electrolytes, massage -- with and without topical analgesics or ointments -- soaks in a hot tub with Epsom salts, stretching, not stretching, etc... I pretty much got nuthin'. Magnesium supplements, especially the mag lactate type, sure seems to help more than most other orally ingested stuff.
Sometimes when it's bad enough I take a muscle relaxer, which does work. My doctors are familiar with my medical history so I have a long term prescription. I seldom use them, maybe once a month, because the pills make me feel sluggish and drowsy for 24-48 hours, and I prefer to stay physically active. Mostly I've used cyclobenzaprine, but I might ask my doc about baclofen to see if it's any better with fewer side effects.