SELECT 
  * 
FROM 
  cscart_product_bundles as bundles 
  LEFT JOIN cscart_product_bundle_descriptions as descriptions ON bundles.bundle_id = descriptions.bundle_id 
  AND descriptions.lang_code = 'en' 
  LEFT JOIN cscart_product_bundle_product_links as links ON bundles.bundle_id = links.bundle_id 
WHERE 
  1 = 1 
  AND (
    (
      links.product_id = '21464' 
      AND links.all_variants = 'Y'
    ) 
    OR links.product_id = '2318'
  ) 
  AND links.show_on_product_page = 'Y' 
  AND bundles.status = 'A' 
GROUP BY 
  bundles.bundle_id 
ORDER BY 
  bundles.bundle_id asc 
LIMIT 
  0, 30

Query time 0.00109

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "bundles.bundle_id",
      "temporary_table": {
        "nested_loop": [
          {
            "table": {
              "table_name": "links",
              "access_type": "range",
              "possible_keys": ["PRIMARY", "bundle_id"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "rows": 2,
              "filtered": 100,
              "index_condition": "links.product_id = '21464' or links.product_id = '2318'",
              "attached_condition": "(links.product_id = '21464' and links.all_variants = 'Y' or links.product_id = '2318') and links.show_on_product_page = 'Y'"
            }
          },
          {
            "table": {
              "table_name": "bundles",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "4",
              "used_key_parts": ["bundle_id"],
              "ref": ["dev_db.links.bundle_id"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "bundles.`status` = 'A'"
            }
          },
          {
            "table": {
              "table_name": "descriptions",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "10",
              "used_key_parts": ["bundle_id", "lang_code"],
              "ref": ["dev_db.links.bundle_id", "const"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond(descriptions.lang_code = 'en')"
            }
          }
        ]
      }
    }
  }
}