SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8cf1e9ceb849490f5a755f6f9b161cafb25e31b4fe5cac33a1909bda5a7eeff' 
  AND token = 'QGt5lQLtkD9daTdxodiRU41KblxcD2PKtcI/PwJ6s+Y=' 
  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