Hi Ankit, 

Thanks for asking, No you cannot check JEE mains answer key online before 24th April.

The Paper codes for JEE Main 2018 exam are A, B, C and D. The answer keys by leading coaching centres will be available on April 8 by late afternoon. CBSE will release the answer key of JEE Main 2018 (Paper I) from April 24 to 27, 2018 along with the recorded responses of the candidates who can check/ view/ challenge the same by April 27, 2018. While challenging JEE Main 2018 answer key, the candidates also have to submit the proof to prove their challenge for a particular question. The answer keys can be checked and downloaded by the candidates to estimate their probable score in JEE Main. The answer key of JEE Main paper II will be released in May 2018. 

Good Luck!