Does crystal leads have to be same length?
Note that in your particular example, it'd be easy to make the traces have the same length – just route them as differential pair up to the middle of your oscillator and split there.

Now, in general, trace length does matter, since it's the job of the oscillator to keep in a sustaining loop of oscillation through an amplifying circuitry that also does a defined phase shift (typically, 180°), and if your traces were wildly different, than that phase shift would become different and the oscillation unstable.

However, a couple of degrees phase imbalance won't matter here. As a rule of thumb, less than \$\frac1{10}\$ of a wavelength is OK – and wavelength is dictated by your oscillator's frequency, dividing the speed of wave propagation in your PCB (most probably, something like \$\frac23c_0\$). 

Taking a 40 MHz oscillator as an example, that would lead to \$\lambda=5\,\text m\$, and your puny board probably is smaller than half a meter :)

What's really interesting, though, is whether your lines' lengths add significant capacitance to your oscillating circuitry, because that would reduce the frequency.