diff --git a/lib/miga/metadata.rb b/lib/miga/metadata.rb
index f96b568..00dcf8f 100644
--- a/lib/miga/metadata.rb
+++ b/lib/miga/metadata.rb
@@ -116,7 +116,7 @@ def lock_file
   ##
   # Return the value of +k+ in #data
   def [](k)
-    if k.to_s =~ /(.+):(.+)/
+    if k.to_s =~ /^([^:]+):(.+)$/
       data[$1.to_sym]&.fetch($2)
     else
       data[k.to_sym]