Is it possible to compare the system time with the time for a JOB?
Something like:

global class AAAExporterCSV implements System.Schedulable {
global void execute(SchedulableContext sc) {
List<case> caseFermeList = [Select casenumber,subject,Contact.Name,status from case where closeddate=TODAY];
string titre= 'Id, Subject,Demandeur,Status'+'\n';
string contenuCSV = titre;
for(Case a: caseFermeList )
if(DateTime.Now() == SCHEDULABLEJOB.Time){
if(a.closeddate == system.Today()){
{
   string contenu = a.casenumber + ',' + a.subject+ ',' +a.Contact.Name+ ',' + a.status +'\n';
   contenuCSV = contenuCSV + contenu ;
}
Messaging.EmailFileAttachment csvPJ = new Messaging.EmailFileAttachment();
blob csvBlob = Blob.valueOf(contenuCSV);
string csvNom = 'cases_fermes.csv';
csvPJ.setFileName(csvNom);
csvPJ.setBody(csvBlob);
Messaging.SingleEmailMessage email =new Messaging.SingleEmailMessage();
String[] adressMail = new list<string> {'v.u@uoly.com'};
String subject = 'report';
email.setSubject(subject);
email.setToAddresses( adressMail );
email.setPlainTextBody('Hi ....');
email.setFileAttachments(new Messaging.EmailFileAttachment[]{csvPJ});
Messaging.SendEmailResult [] envoyer = Messaging.sendEmail(new Messaging.SingleEmailMessage[] {email});
  }
  }
  }
}



Thank you!