diff --git a/marconi-chain-index/src/Marconi/ChainIndex/Indexers/MintBurn.hs b/marconi-chain-index/src/Marconi/ChainIndex/Indexers/MintBurn.hs
index b1d05f61ed..6326b7dd70 100644
--- a/marconi-chain-index/src/Marconi/ChainIndex/Indexers/MintBurn.hs
+++ b/marconi-chain-index/src/Marconi/ChainIndex/Indexers/MintBurn.hs
@@ -333,8 +333,9 @@ instance RI.Queryable MintBurnHandle where
       -- * Filter in-memory events
 
       upToSlot :: Maybe C.SlotNo -> [TxMintRow -> Bool]
-      upToSlot maybeSlotNo =
-        maybe [] (\slotNo -> [\row -> _txMintRowSlotNo row <= slotNo]) maybeSlotNo
+      upToSlot = \case
+        Just slotNo -> [\row -> _txMintRowSlotNo row <= slotNo]
+        Nothing     -> []
 
       matchesAssetId :: C.PolicyId -> C.AssetName -> TxMintRow -> Bool
       matchesAssetId policyId assetName row =
@@ -374,7 +375,7 @@ instance RI.Queryable MintBurnHandle where
         )
 
       mkUpperBoundCondition :: Maybe C.SlotNo -> ([SQL.Query], [NamedParam])
-      mkUpperBoundCondition maybeUpperBound = case maybeUpperBound of
+      mkUpperBoundCondition = \case
         Nothing -> ([], [])
         Just s  -> (["slotNo <= :slotNo"] , [":slotNo" := s])