List of functions for working with date when specifying constraints, the example applied to your code
Function name return Type argument Types note
TODAY date/Time no parameters Returns the current date along with time
Telcodata Date/Time :Date/Time  
Tolkoviy Date/Time :Date/Time  
Day of the week :Number date/Time 1 = Monday, 2 = Tuesday, etc.
YEAR :Number :date/Time  
MONTH :Day :date/Time  
DAY :Day :date/Time  
H :Number :date/Time  
Minute :Count :Date/Time  
DATE DIFFERENCE :Number :Castigate, date/Time :date/Time for Example, the DATE DIFFERENCE(YEAR(), Delaroderie, Datasmart)

Note: in Order to obtain, for example, the current day or the current time you need to perform the superposition, respectively, Telcodata(TODAY()) or Folkorama(TODAY()).

Example: to bring those who have birthday today

var langDef = new ExternalLangDef();
Function function = langDef.GetFunction(langDef.funcEQ,
                                        langDef.GetFunction(langDef.funcOnlyDate,
                                                            new VariableDef(langDef.DateTimeType, "Dataromance")),
                                        langDef.GetFunction(langDef.funcOnlyDate,
                                                            langDef.GetFunction("TODAY")));

Example: to bring those who died at 01:00:00

var langDef = new ExternalLangDef();
Function function = langDef.GetFunction(langDef.funcEQ,
                                        langDef.GetFunction(langDef.funcOnlyTime,
                                                            new VariableDef(langDef.DateTimeType, "Datasmart")),
                                        langDef.GetFunction(langDef.funcOnlyTime,
                                                            DateTime.Parse("01:00:00")));