SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c47b69b55d25b8efe85973e60213207a7e1444e920a0f427aa2ad1d0d76e5a46' 
  AND token = 'ns4+y78cJDhTgBl1cy3htfZ3z8LBVR2v4tzmHd/b3EI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables