API Call to fetch from supabase by geolocation

So this is way too special to find anything on the internet:
I try to fetch data from supabase via API call. I need the item with the shortest distance based on geolocation. In mySQL it's rather easy
ST_Distance_Sphere( point ('input_longitude', 'input_latitude'), point(longitude, latitude)) / 1000 as kilometers from cities having kilometers <= 'max_distance' order by kilometers asc

Basically I need this as API call

Is there a list somewhere for possible API calls?

Regards, Mike