SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a71dfd9cb9e2f6c51910346601cb87eea4eec28baf18dcdb9584b7dea16fd94b' 
  AND token = 'tb8NTQ89SHFjcwOrkTVD3sL6ZRzfjjVu2OdCo/bX7RY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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