Sorry to spam, just to add, the other 2 columns, on which its not doing a key look up (Message, Datetimestamp) are not part of the clustered index. Here's the entire table + index definition:
CREATE TABLE [tblBIUsers](
[BIUserID] [bigint] IDENTITY(1,1) NOT NULL,
[LoginName] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[Password] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[FirstName] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
[MiddleName] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[LastName] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL,
[Gender] [char](1) COLLATE SQL_Latin1_General_CP1_CI_AS NOT NULL CONSTRAINT [DF_tblBIUsers_Gender] DEFAULT ('X'),
[Email] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[Student] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[OrganisationID] [bigint] NULL,
[TestBatchID] [uniqueidentifier] NOT NULL,
[TestPartSeqNumber] [int] NOT NULL,
[TestBatchName] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[RuTestBatchID] [varchar](50) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[RuTestBatchStatus] [tinyint] NULL,
[UserStatus] [tinyint] NULL,
[Message] [nvarchar](100) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
[CourseID] [bigint] NULL,
[IsDeleted] [bit] NOT NULL CONSTRAINT [DF_tblBIUsers_IsDeleted] DEFAULT ((0)),
[DateTimeStamp] [datetime] NOT NULL CONSTRAINT [DF_tblBIUsers_DateTimeStamp] DEFAULT (getdate()),
[DateTimeStampIns] [datetime] NOT NULL CONSTRAINT [DF_tblBIUsers_DateTimeStampIns] DEFAULT (getdate()),
[UploadedUserID] [bigint] NULL,
[UploadedDate] [datetime] Not NULL CONSTRAINT [DF_tblBIUsers_UploadedDate] DEFAULT (getutcdate()),
[BusinessRuleSet] [varchar](15) COLLATE SQL_Latin1_General_CP1_CI_AS NULL,
CONSTRAINT [PK_tblBIUsers] PRIMARY KEY NONCLUSTERED
(
[BIUserID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY]
IF NOT EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[tblBIUsers]') AND name = N'CIX_tblBIUsers')
CREATE CLUSTERED INDEX [CIX_tblBIUsers] ON [tblBIUsers]
(
[TestBatchID] ASC,
[TestPartSeqNumber] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
IF NOT EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[tblBIUsers]') AND name = N'IX_tblBIUsersRuTestTestMap')
CREATE NONCLUSTERED INDEX [IX_tblBIUsersRuTestTestMap] ON [tblBIUsers]
(
[RuTestBatchID] ASC,
[TestPartSeqNumber] ASC
)
WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
IF NOT EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[tblBIUsers]') AND name = N'IX_tblBIUsersUplDtPwdIsDel')
CREATE NONCLUSTERED INDEX [IX_tblBIUsersUplDtPwdIsDel] ON [tblBIUsers]
(
[UploadedDate] ASC,
[Password] ASC,
[IsDeleted] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO
IF NOT EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[tblBIUsers]') AND name = N'IX_tblBIUsers_OCU')
CREATE NONCLUSTERED INDEX [IX_tblBIUsers_OCU] ON [tblBIUsers]
(
[OrganisationID] ASC,
[CourseID] ASC,
[UploadedUserID] ASC
)
INCLUDE ( [UploadedDate],
[RuTestBatchID],
[RuTestBatchStatus],
[UserStatus],
[IsDeleted]) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
GO