Toast spices in a medium frying pan over medium heat until fragrant and coriander seeds are light golden, about 4 minutes. Coarsely grind in a mortar or spice grinder, then pour onto a plate.
Heat oil in a 12-in. nonstick frying pan over medium-high heat. Season scallops with salt right before cooking and dredge top and bottom of each one in spice mix.
Cook scallops until golden underneath, about 3 minutes, then flip and cook until just cooked through, 2 to 3 minutes.