SELECT 
  products.product_id 
FROM 
  jmj_products AS products 
WHERE 
  products.master_product_id = 1439 
  AND products.status IN ('A') 
  AND products.amount > 0

Query time 0.00055

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "3.60"
    },
    "table": {
      "table_name": "products",
      "access_type": "ref",
      "possible_keys": [
        "status",
        "idx_master_product_id"
      ],
      "key": "idx_master_product_id",
      "used_key_parts": [
        "master_product_id"
      ],
      "key_length": "4",
      "ref": [
        "const"
      ],
      "rows_examined_per_scan": 3,
      "rows_produced_per_join": 0,
      "filtered": "31.44",
      "cost_info": {
        "read_cost": "3.00",
        "eval_cost": "0.19",
        "prefix_cost": "3.60",
        "data_read_per_join": "4K"
      },
      "used_columns": [
        "product_id",
        "status",
        "amount",
        "master_product_id"
      ],
      "attached_condition": "((`jmj_test`.`products`.`status` = 'A') and (`jmj_test`.`products`.`amount` > 0))"
    }
  }
}