SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0495f62498a1e78ef7193502ed135d10d690cbbd499bc012a888c00f744680f' 
  AND token = 'iQN+VtQNltTYDF9KjuQo7ASeR/tRag3EdbKnyixok5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

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