SELECT 
  cscart_kl_containers.* 
FROM 
  cscart_kl_containers 
WHERE 
  1 
  AND `cscart_kl_containers`.`storefront_id` = 1 
  AND cscart_kl_containers.user_id IN (65882) 
  AND cscart_kl_containers.privacy_type = 'public' 
ORDER BY 
  cscart_kl_containers.title asc

Query time 0.00079

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "1209.47"
    },
    "ordering_operation": {
      "using_filesort": false,
      "table": {
        "table_name": "cscart_kl_containers",
        "access_type": "ref",
        "possible_keys": [
          "idx_kl_containers"
        ],
        "key": "idx_kl_containers",
        "used_key_parts": [
          "privacy_type"
        ],
        "key_length": "1",
        "ref": [
          "const"
        ],
        "rows_examined_per_scan": 1100,
        "rows_produced_per_join": 11,
        "filtered": "1.00",
        "index_condition": "((`cscart_db`.`cscart_kl_containers`.`user_id` = 65882) and (`cscart_db`.`cscart_kl_containers`.`storefront_id` = 1))",
        "cost_info": {
          "read_cost": "1099.48",
          "eval_cost": "1.10",
          "prefix_cost": "1209.48",
          "data_read_per_join": "15K"
        },
        "used_columns": [
          "container_id",
          "user_id",
          "session_id",
          "timestamp",
          "ip",
          "is_default",
          "title",
          "category_id",
          "skey",
          "note",
          "tags",
          "company_id",
          "storefront_id",
          "privacy_type",
          "isparent",
          "parent_id",
          "og_image"
        ]
      }
    }
  }
}