diff --git a/cashu/mint/crud.py b/cashu/mint/crud.py
index fd95317a..853ff094 100644
--- a/cashu/mint/crud.py
+++ b/cashu/mint/crud.py
@@ -47,8 +47,8 @@ async def get_spent_proofs(
     async def get_proof_used(
         self,
         *,
-        db: Database,
         Y: str,
+        db: Database,
         conn: Optional[Connection] = None,
     ) -> Optional[Proof]: ...
 
@@ -598,8 +598,9 @@ async def get_keyset(
 
     async def get_proof_used(
         self,
-        db: Database,
+        *,
         Y: str,
+        db: Database,
         conn: Optional[Connection] = None,
     ) -> Optional[Proof]:
         row = await (conn or db).fetchone(
diff --git a/cashu/mint/verification.py b/cashu/mint/verification.py
index 25fa2ae3..e3da1d54 100644
--- a/cashu/mint/verification.py
+++ b/cashu/mint/verification.py
@@ -163,8 +163,9 @@ async def _get_proofs_spent_idx_secret(
         if settings.mint_cache_secrets:
             # check used secrets in memory
             for proof in proofs:
-                if proof.Y in self.spent_proofs:
-                    proofs_spent.append(proof)
+                spent_proof = self.spent_proofs.get(proof.Y)
+                if spent_proof:
+                    proofs_spent.append(spent_proof)
         else:
             # check used secrets in database
             async with self.db.connect() as conn: