For values no smaller than 1:
[~, binx] = histc(x, [x_values(:); inf]);
[~, biny] = histc(y, [y_values(:); inf]);
this assumes that values might be greater than x_values(end) -- for example with x_values = 1:10 then this code assumes that 10.32403 might be a valid input. If that is not the case you need to decide whether x_values(end) exactly is a valid input and if so whether you want it to go into the bin that starts at x_values(end-1) -- e.g., should 10 exactly go into the same bin as [9,10) or should it go into a bin by itself. If you want it to go into the same bin as [9,10), making that bin [9,10] (inclusive on both sides), an asymmetry as all the other bins will be semi-open, then
[~, binx] = histc(x, [reshape(x_values(1:end-1),,1); inf]);
Also this assumes that there are no values lower than x_values(1). If there are then do you want them discarded or do you want them placed in a bin by themselves, or do you want them in the same bin as the first defined range?