Most efficient way to filter on two columns in WHERE clause?
Here is the FROM (VALUES... version, with an EXISTS thrown in to get some speedy search shortcuts happening:

SELECT *
FROM tbltrainerinfo
WHERE EXISTS(
    SELECT *
    FROM (VALUES
        ('Arpay','Belly Joy')
        ,('Bebelyn','Abulog')
        ,('Cabrera','Virgie')
        ,('Christopher','Sajonia')
        ,('Edilberto','Galaura')
        ,('Embanecido','Efren')
        ,('Gertrulyn','Natonton')
        ,('Gina','Gindap')
        ,('Gindap','Gina')
        ,('Jeffrey','Ladiero')
        ,('JIMENEZ','JUNPORT')
        ,('Jocelyn','Paloma')
        ,('Ladera','Chared')
        ,('Lago','Michelle Joy')
        ,('Maratima','Untal')
        ,('Marciano','Iloreta')
        ,('Marianita','Gemina')
        ,('Pala','Sittie Norjanna')
        ,('Untal','Maratima')
        ) AS List(LName, FName)
    WHERE LName = lastName
      AND FName = firstname
    )