As I know, neutron stars are almost perfect sphere and no net moments, does it mean it is not possible to tidally lock it?
If a neutron star were a perfect sphere with a monopole moment and zero quadrupole, etc., moments, it would be impossible to observe its rotation. For example, observe the rotation of Earth's roundest object (whose rotational symmetry is broken by its crystalline structure).
We are able to observe that neutron stars rotate. Therefore neutron stars have nonzero moments of inertia and are subject to tidal locking. However it might take a very long time. A commenter links to a paper on the subject.