there's hardly any spacing between the two.
Worse than that, since that doesn't look like a very accurate outline for a typical crystal!
Otherwise, the SMD pads should not affect the accuracy in any meaningful way. (oh, let's plug in numbers!
Assume a pad 2mm on a side, with a separation of 1.6mm from the other plate, and a dielectric constant of 4 for fiberglass PCB material.)
C = Er * E0 * A/d
= 4 * 9e-12 * (2e-3 * 2e-3)/1.6e-3
= 0.1 pF (approx)
Here's the layout from one of the official arduino boards, BTW: