Custom Bearer Token Authorization for ASP.Net Core

Is this an acceptable implementation of a custom bearer token authorization mechanism?

Authorization Attribute

public class AuthorizeAttribute : TypeFilterAttribute
{
    public AuthorizeAttribute(): base(typeof(AuthorizeActionFilter)){}
}

public class AuthorizeActionFilter : IAsyncActionFilter
{
    private readonly IValidateBearerToken _authToken;
    public AuthorizeActionFilter(IValidateBearerToken authToken)
    {
        _authToken = authToken;
    }

    public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
    {
        const string AUTHKEY = "authorization";
        var headers = context.HttpContext.Request.Headers;
        if (headers.ContainsKey(AUTHKEY))
        {
            bool isAuthorized = _authToken.Validate(headers[AUTHKEY]);
            if (!isAuthorized)
                context.Result = new UnauthorizedResult();
            else
                await next();
        }
        else
            context.Result = new UnauthorizedResult();
    }
}

Validation Service. APISettings class is used in appSettings, but validation can be extended to use a database ... obviously :)

public class APISettings
{
    public string Key { get; set; }
}

public class ValidateBearerToken : IValidateBearerToken
{
    private readonly APISettings _bearer;

    public ValidateBearerToken(IOptions<APISettings> bearer)
    {
        _bearer = bearer.Value;
    }

    public bool Validate(string bearer)
    {
        return (bearer.Equals($"Bearer {_bearer.Key}"));
    }
}

Implementation

[Produces("application/json")]
[Route("api/my")]
[Authorize]
public class MyController : Controller

appSettings

"APISettings": {
"Key": "372F78BC6B66F3CEAF705FE57A91F369A5BE956692A4DA7DE16CAD71113CF046"

}

Request Header

Authorization: Bearer 372F78BC6B66F3CEAF705FE57A91F369A5BE956692A4DA7DE16CAD71113CF046