Using numpy and the numpy.where function is very powerfull. If you want to use several conditions with np.where you have to use the bitwise-AND-operator to combine to different conditions in one query. Of course you can also use the bitwise OR-operator too.

daten = np.random.rand(50,5)
sel = np.where((daten[:,0]==5) & (daten[:,1]< 17))[0]
plt.scatter(daten[sel,3], daten[sel,4])