SELECT 
  v.data 
FROM 
  cscart_product_variation_variety AS v 
  JOIN cscart_product_variation_group_products AS g ON v.group_id = g.group_id 
WHERE 
  g.product_id = 7470 
  AND v.type = 'P'

Query time 0.00059

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "0.70"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "g",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "product_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": "0.25",
            "eval_cost": "0.10",
            "prefix_cost": "0.35",
            "data_read_per_join": "16"
          },
          "used_columns": [
            "product_id",
            "group_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "v",
          "access_type": "ref",
          "possible_keys": [
            "idx_cscart_product_variation_variety"
          ],
          "key": "idx_cscart_product_variation_variety",
          "used_key_parts": [
            "group_id",
            "type"
          ],
          "key_length": "7",
          "ref": [
            "chocoramo.g.group_id",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "index_condition": "(`chocoramo`.`v`.`group_id` = `chocoramo`.`g`.`group_id`)",
          "cost_info": {
            "read_cost": "0.25",
            "eval_cost": "0.10",
            "prefix_cost": "0.70",
            "data_read_per_join": "792"
          },
          "used_columns": [
            "group_id",
            "type",
            "data"
          ]
        }
      }
    ]
  }
}