SELECT 
  w_prods.* 
FROM 
  cscart_kl_container_contents as w_prods 
  LEFT JOIN cscart_product_descriptions as descr ON descr.product_id = w_prods.content_id 
  AND content_type = "product" 
  AND lang_code = 'en' 
WHERE 
  1 
  AND w_prods.container_id = 133919 
ORDER BY 
  descr.product ASC

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.42"
    },
    "ordering_operation": {
      "using_temporary_table": true,
      "using_filesort": true,
      "cost_info": {
        "sort_cost": "5.00"
      },
      "nested_loop": [
        {
          "table": {
            "table_name": "w_prods",
            "access_type": "ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "container_id"
            ],
            "key_length": "3",
            "ref": [
              "const"
            ],
            "rows_examined_per_scan": 5,
            "rows_produced_per_join": 5,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "1.01",
              "eval_cost": "0.50",
              "prefix_cost": "1.51",
              "data_read_per_join": "200"
            },
            "used_columns": [
              "container_id",
              "cart_id",
              "content_type",
              "content_id",
              "product",
              "note"
            ]
          }
        },
        {
          "table": {
            "table_name": "descr",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY",
              "product_id",
              "idx_product_desc_lang",
              "idx_product_name_search",
              "idx_product_desc_sort"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "product_id",
              "lang_code"
            ],
            "key_length": "9",
            "ref": [
              "cscart_db.w_prods.content_id",
              "const"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 5,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "3.41",
              "eval_cost": "0.50",
              "prefix_cost": "5.42",
              "data_read_per_join": "22K"
            },
            "used_columns": [
              "product_id",
              "lang_code",
              "product"
            ],
            "attached_condition": "<if>(is_not_null_compl(descr), (`cscart_db`.`w_prods`.`content_type` = 'product'), true)"
          }
        }
      ]
    }
  }
}