fix(events): keep registration status reads nonblocking

apps/payments/api/views.py

@@ -18,7 +18,7 @@ from apps.payments.models import Payment, DiscountCode
 from apps.events.models import Event, Registration
 from apps.events.checkout import (
     CHECKOUT_TIMEOUT,
-    expire_stale_registration_checkouts,
+    expire_user_registration_checkouts,
     queue_checkout_reconciliation,
 )
 from apps.notifications.services import notify_user
@@ -316,8 +316,13 @@ def _ensure_checkout_attempt_can_be_reused(payment: Payment, *, now, allow_revie
 def create_payment(request, payload: CreatePaymentIn):
     idempotency_key = payload.idempotency_key or uuid4()
     now = timezone.now()
-    expire_stale_registration_checkouts(now=now, event_id=payload.event_id)
-
+    with transaction.atomic():
+        event = get_object_or_404(
+            Event.objects.select_for_update(),
+            pk=payload.event_id,
+            is_deleted=False,
+        )
+        expire_user_registration_checkouts(event=event, user=request.auth, now=now)
     # Serialize checkout creation for this event so concurrent taps cannot
     # both create a new active attempt for the same user/event pair.
     with transaction.atomic():