SELECT 
  parent_product_id 
FROM 
  tmall_product_variation_group_products 
WHERE 
  product_id = 282 
  AND group_id = 10

Query time 0.00851

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "tmall_product_variation_group_products",
          "access_type": "const",
          "possible_keys": ["PRIMARY", "idx_group_id"],
          "key": "PRIMARY",
          "key_length": "6",
          "used_key_parts": ["product_id", "group_id"],
          "ref": ["const", "const"],
          "rows": 1,
          "filtered": 100
        }
      }
    ]
  }
}