TOPIC:

uses
  cthreads,
  (...) 
  SQLdb, MySQL55conn;

(...)

procedure blah;
var
  MySQLconnection : TMySQL55Connection;
  MySQLtransaction : TSQLTransaction;
  MySQLquery : TSQLQuery;

begin
  MySQLconnection := TMySQL55Connection.Create( nil );
  MySQLtransaction := TSQLTransaction.Create( nil );
  MySQLquery := TSQLQuery.Create( nil );

  MySQLconnection.Transaction := MySQLtransaction;
  MySQLtransaction.DataBase := MySQLconnection;
  MySQLquery.DataBase := MySQLconnection;
  MySQLquery.Transaction := MySQLtransaction;
  MySQLquery.ParseSQL := False;

  MySQLconnection.HostName := 'localhost';
  MySQLconnection.Port := 3306;
  MySQLconnection.UserName := 'user';
  MySQLconnection.Password := 'pass';
  MySQLconnection.DatabaseName := 'dbname';

  MySQLconnection.Open;
  MySQLtransaction.StartTransaction;

  MySQLquery.SQL.Clear;
  MySQLquery.SQL.Add( 'SELECT * FROM seriale_ustawienia' );
  MySQLquery.Open;                        <===== dies here with that non-select exception
  while ( not MySQLquery.EOF ) do
    begin

(...)

end;