[SalesForce] How we can export data with apex data loader using record ids only

2013-06-11T15:54:00Z is GMT The Z at the end signifies Zulu which is UTC or GMT All times are stored in the database as GMT times and then corrected for display based on the Users Timezone

So you can either convert to GMT and then query 2013-06-11T13:54:00Z (GMT = CET - 2?)

If you're concerned about time or memory limits, use a batch class. This is how I would perform the export of a potentially unknown size (10k+ records).

global class X implements Database.Batchable<SObject>, Database.Stateful {
    string[] Lines;

    global Database.QueryLocator start(Database.BatchableContext bc) {
        lines = new String[0];
        return Database.getQueryLocator( your-query-here );
    }
    global void execute(Database.BatchableContext bc, SObject[] scope) {
        for(Sobject record: scope) {
            String line = '';
            // build your csv line here
            lines.add(line);
        }
    }
    global void finish(Database.batchablecontext bc) {
        String finalResults = String.join(lines, '\n');
        lines = null; // Free temp memory to avoid heap errors
        // proceed to send attachment by email
    }
}

The best performance I've gotten for a synchronous export (that is, a direct query, plus processing about 30 fields per record) is about 5,000 records before a CPU timeout exception, so if this is a concern, definitely go with a batch. If you're confident that you can beat the timeout, you could perform the query and translation directly in the scheduler class itself without resorting to a batch.