SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6847a7d15c68eee69cbd3a1a423076981a2918c6e5ccbaed818faadd1313a37' 
  AND token = 'GiOpaCCioJh6itAangG+OnTQpKUwa9Ws+0yXezeGUH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

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