If Pyke dies and an enemy unit dies at the same time, does Pyke still grant 1 gold?

No, Pyke will not grant the gold token in that scenario.

Because Pyke's ability ("Once each turn, when an enemy unit dies while I'm at a battlefield...") requires him to be at a battlefield to trigger, he must be present on the board to "see" the death of the enemy unit. If Pyke dies at the same time as the enemy unit, he is no longer on the board at the moment the death condition is evaluated, and therefore his ability does not trigger. This is further supported by similar rulings in the RiftJudge FAQ (e.g., FAQ #7662 and #3223 regarding Viktor, Leader), which establish that units must remain in play to see simultaneous events.

Note: I could not fully verify this ruling against the retrieved rules.