What is Corporate social responsibility in reality? How we can see this mythical concept in current era?

It doesn't exist.  It can't doesn't exist, because it doesn't make any sense.  A body corporate established to undertake social projects isn't exercising CSR because that's it's mission anyway.  A body corporate established for commercial purposes (i.e. a business) can't do "pure" CSR because that would be a breach of its legal obligations.

However, "fake" CSR obviously does exist.  It comes in three distinct forms:

1) Real activities undertaken at the behest of senior figures in the company.  This is most common in organisations controlled by strong figures, often the founder, who have a real desire to do something in the community.  Mostly these activities, although worthwhile, just annoy everybody else in the company.

2) CSR smoke and mirrors.  This is common in large companies: swathes of the annual report are devoted to the good deeds they alledgedly do, and vast numbers of boxes are ticked.  Whether or not any actual good is done, or indeed anything at all is done is moot.

3) The real thing.  Well run companies have targetted CSR activities which support the brand, motivate the staff, impress the customers, and generally inspire the other stakeholders.  These activities both do real good in the community, and are also commercially advantageous.  This is a difficult trick to pull off, and it is rarely achieved successfully.