diff --git a/src/libstore/binary-cache-store.hh b/src/libstore/binary-cache-store.hh
index e369abe46..574696cf3 100644
--- a/src/libstore/binary-cache-store.hh
+++ b/src/libstore/binary-cache-store.hh
@@ -54,9 +54,6 @@ public:
 
     bool isValidPathUncached(const Path & path) override;
 
-    PathSet queryValidPaths(const PathSet & paths) override
-    { notImpl(); }
-
     PathSet queryAllValidPaths() override
     { notImpl(); }
 
diff --git a/src/libstore/store-api.cc b/src/libstore/store-api.cc
index 74014b47e..a830ae5bb 100644
--- a/src/libstore/store-api.cc
+++ b/src/libstore/store-api.cc
@@ -361,6 +361,17 @@ void Store::queryPathInfo(const Path & storePath,
 }
 
 
+PathSet Store::queryValidPaths(const PathSet & paths)
+{
+    PathSet valid;
+
+    for (auto & path : paths)
+        if (isValidPath(path)) valid.insert(path);
+
+    return valid;
+}
+
+
 /* Return a string accepted by decodeValidPathInfo() that
    registers the specified paths as valid.  Note: it's the
    responsibility of the caller to provide a closure. */
diff --git a/src/libstore/store-api.hh b/src/libstore/store-api.hh
index b876ffbba..ce1583b0c 100644
--- a/src/libstore/store-api.hh
+++ b/src/libstore/store-api.hh
@@ -306,7 +306,7 @@ protected:
 public:
 
     /* Query which of the given paths is valid. */
-    virtual PathSet queryValidPaths(const PathSet & paths) = 0;
+    virtual PathSet queryValidPaths(const PathSet & paths);
 
     /* Query the set of all valid paths. Note that for some store
        backends, the name part of store paths may be omitted