Hot backup with InnODB, without affecting the end users is possible only with the Enterprise edition or Percona using mysqlbackup or Xtrabackup respectively. The mysqlbackup can be downloaded as trial in order to be tested of course. Once the executable is available can be used as follows

[root@mysqlslave ~]# ./mysqlbackup --port=3306 --protocol=tcp --user=root --password=password --with-timestamp --backup-dir=/backup backup-and-apply-log
MySQL Enterprise Backup version 4.1.0 Linux-4.1.12-61.1.16.el7uek.x86_64-x86_64 [2017/03/01]
Copyright (c) 2003, 2017, Oracle and/or its affiliates. All Rights Reserved.

180211 14:33:35 MAIN    INFO: A thread created with Id '139810546444096'
180211 14:33:35 MAIN    INFO: Starting with following command line ...
 ./mysqlbackup --port=3306 --protocol=tcp --user=root
        --password=xxxxxxxxxxxx --with-timestamp --backup-dir=/backup
        backup-and-apply-log

180211 14:33:35 MAIN    INFO:
180211 14:33:35 MAIN    INFO: MySQL server version is '5.7.21-log'
180211 14:33:35 MAIN    INFO: MySQL server compile os version is 'Linux'
180211 14:33:35 MAIN    INFO: Got some server configuration information from running server.

180211 14:33:35 MAIN    INFO: Server system variable 'old_alter_table' was set to '0'. Setting it to '1'.
IMPORTANT: Please check that mysqlbackup run completes successfully.
           At the end of a successful 'backup-and-apply-log' run mysqlbackup
           prints "mysqlbackup completed OK!".

180211 14:33:35 MAIN    INFO: MEB logfile created at /backup/2018-02-11_14-33-35/meta/MEB_2018-02-11.14-33-35_backup_apply_log.log

Mysqlbackup doesn't do magic :) Datafiles cannot be changed while the backup is being done, that's why any change which is performed is written to the binary log instead to the disk, after the backup is done, the log files are applied with the: “backup-and-apply-log” option.

Once the backup is done, you can see the files below the output:

InnoDB: Progress in percent: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
180211 14:33:40 PCR1    INFO: InnoDB: Setting log file size to 50331648.
180211 14:33:41 PCR1    INFO: InnoDB: Setting log file size to 50331648.
180211 14:33:42 PCR1    INFO: We were able to parse ibbackup_logfile up to
          lsn 2596922.
180211 14:33:42 PCR1    INFO: Last MySQL binlog file position 0 154, file name mysqlslave-bin.000003
180211 14:33:42 PCR1    INFO: The first data file is '/backup/2018-02-11_14-33-35/datadir/ibdata1'
                              and the new created log files are at '/backup/2018-02-11_14-33-35/datadir'
180211 14:33:42 MAIN    INFO: Apply-log operation completed successfully.
180211 14:33:42 MAIN    INFO: Full backup prepared for recovery successfully.

mysqlbackup completed OK! with 60 warnings