diff --git a/src/wp-includes/wp-db.php b/src/wp-includes/wp-db.php
index 7dd81b89cc..489b80d3fb 100644
--- a/src/wp-includes/wp-db.php
+++ b/src/wp-includes/wp-db.php
@@ -2405,6 +2405,11 @@ class wpdb {
 			return true;
 		}
 
+		// All-ASCII queries don't need extra checking.
+		if ( $this->check_ascii( $query ) ) {
+			return true;
+		}
+
 		$table = $this->get_table_from_query( $query );
 		if ( ! $table ) {
 			return false;
diff --git a/tests/phpunit/tests/db/charset.php b/tests/phpunit/tests/db/charset.php
index d55c750c66..3e0b81ad8a 100755
--- a/tests/phpunit/tests/db/charset.php
+++ b/tests/phpunit/tests/db/charset.php
@@ -503,9 +503,10 @@ class Tests_DB_Charset extends WP_UnitTestCase {
 			$this_table_name = $table_name . '_' . rand_str( 5 );
 
 			$value[0] = "CREATE TABLE $this_table_name {$value[0]}";
-			$value[2] = "SELECT * FROM $this_table_name";
+			$value[2] = "SELECT * FROM $this_table_name WHERE a='\xf0\x9f\x98\x88'";
 			$value[3] = "DROP TABLE IF EXISTS $this_table_name";
 			$value[4] = array(
+				"SELECT * FROM $this_table_name WHERE a='foo'",
 				"SHOW FULL TABLES LIKE $this_table_name",
 				"DESCRIBE $this_table_name",
 				"DESC $this_table_name",