diff --git a/Orange/widgets/data/owfeatureconstructor.py b/Orange/widgets/data/owfeatureconstructor.py
index cf745a13979..1469686ab5c 100644
--- a/Orange/widgets/data/owfeatureconstructor.py
+++ b/Orange/widgets/data/owfeatureconstructor.py
@@ -733,11 +733,14 @@ def duplicateFeature(self):
 
     @staticmethod
     def check_attrs_values(attr, data):
-        for i in range(len(data)):
-            for var in attr:
-                if not math.isnan(data[i, var]) \
-                        and int(data[i, var]) >= len(var.values):
-                    return var.name
+        for var in attr:
+            col, _ = data.get_column_view(var)
+            mask = np.isnan(col)
+            mask = np.greater_equal(
+                col, len(var.values), out=mask, where=~mask
+            )
+            if mask.any():
+                return var.name
         return None
 
     def _validate_descriptors(self, desc):