diff --git a/src/Query/TokenType.php b/src/Query/TokenType.php
index 238653018bc..417c7506d25 100644
--- a/src/Query/TokenType.php
+++ b/src/Query/TokenType.php
@@ -4,7 +4,7 @@
 
 namespace Doctrine\ORM\Query;
 
-class TokenType
+final class TokenType
 {
     // All tokens that are not valid identifiers must be < 100
     public const T_NONE              = 1;