SELECT 
  cscart_power_labels.label_id, 
  cscart_power_labels_products.type 
FROM 
  cscart_power_labels 
  LEFT JOIN cscart_power_labels_products ON cscart_power_labels_products.label_id = cscart_power_labels.label_id 
  AND cscart_power_labels_products.product_id = 83883 
WHERE 
  cscart_power_labels_products.type != ''

Query time 0.00048

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "1.00"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_power_labels_products",
          "access_type": "system",
          "possible_keys": [
            "prod_label",
            "label_id",
            "product_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.10",
            "prefix_cost": "0.00",
            "data_read_per_join": "16"
          },
          "used_columns": [
            "product_id",
            "label_id",
            "type"
          ]
        }
      },
      {
        "table": {
          "table_name": "cscart_power_labels",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "label_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "using_index": true,
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.10",
            "prefix_cost": "0.00",
            "data_read_per_join": "2K"
          },
          "used_columns": [
            "label_id"
          ]
        }
      }
    ]
  }
}