how to optimize the queries to reduce load on the server

i have a table with 1505260 rows,
when i am executing this Query
select user_id from tbl_Payment_master Run time should be 00:00:25,how to reduce it ,there is any other way to optimize this.
this is my table structure
CREATE TABLE [dbo].[tbl_payment_master]( [payment_Id] [bigint] IDENTITY(1,1) NOT NULL, [advisor_id] [bigint] NULL, [user_id] [bigint] NULL, [premium_amount] [float] NULL, [carry_Amount] [float] NULL, [promotion_id] [bigint] NULL, [No_Of_Due] [bigint] NULL, [paid_date] [datetime] NULL, [user_code] [nvarchar](max) NULL, [employeeId] [bigint] NULL, [year] [nvarchar](max) NULL, [bvamt] [float] NULL, [referral_id] [bigint] NULL, [mode] [nvarchar](max) NULL, [carrybv] [float] NULL, [latefee] [float] NULL, [dummypay] [nvarchar](max) NULL, [delete_status] [bigint] NULL, [paid_on] [datetime] NULL, [deleted_by] [bigint] NULL, [to ...