diff --git a/core/lib/Drupal/Core/Config/Entity/Query/Query.php b/core/lib/Drupal/Core/Config/Entity/Query/Query.php
index b398f83..7f433cb 100644
--- a/core/lib/Drupal/Core/Config/Entity/Query/Query.php
+++ b/core/lib/Drupal/Core/Config/Entity/Query/Query.php
@@ -84,17 +84,19 @@ public function condition($property, $value = NULL, $operator = NULL, $langcode
    * Implements \Drupal\Core\Entity\Query\QueryInterface::execute().
    */
   public function execute() {
-    // Load all config files.
     $entity_info = $this->entityManager->getDefinition($this->getEntityType());
     $prefix = $entity_info['config_prefix'] . '.';
     $prefix_length = strlen($prefix);
-    $names = $this->configStorage->listAll($prefix);
+
+    // Load the relevant config files.
     $configs = array();
+    $names = $this->findNames($entity_info);
     $config_objects = $this->configFactory->loadMultiple($names);
     foreach ($config_objects as $config) {
       $configs[substr($config->getName(), $prefix_length)] = $config->get();
     }
 
+    // Apply conditions.
     $result = $this->condition->compile($configs);
 
     // Apply sort settings.
@@ -124,4 +126,46 @@ public function execute() {
     return $result;
   }
 
+  /**
+   * Determines the names of config records to load for the query.
+   *
+   * @param array $entity_info
+   *   The entity info.
+   *
+   * @return array
+   *   The list of config record names to load.
+   */
+  protected function findNames(array $entity_info) {
+    $prefix = $entity_info['config_prefix'] . '.';
+
+    // If there are conditions on the config id, we can narrow the list of
+    // config records to load and parse.
+    $ids = array();
+    if ($this->condition->getConjunction() == 'AND') {
+      foreach ($this->condition->conditions() as $condition) {
+        if ($condition['field'] == $entity_info['entity_keys']['id']) {
+          $operator = $condition['operator'];
+          if (!isset($condition['operator'])) {
+            $operator = is_array($condition['value']) ? 'IN' : '=';
+          }
+          if ($operator == '=' || $operator == 'IN') {
+            $ids = is_array($condition['value']) ? $condition['value'] : array($condition['value']);
+            // We can stop at the first condition on ID. In the (weird) case
+            // where other conditions additionally restrict IDs, results will
+            // be eliminated when the conditions are checked on the loaded
+            // records.
+            break;
+          }
+        }
+      }
+    }
+    if ($ids) {
+      return array_map(function ($id) use ($prefix) {
+        return $prefix . $id;
+      }, $ids);
+    }
+
+    // If no conditions on IDs were found, we need to look at all the records.
+    return $this->configStorage->listAll($prefix);
+  }
 }