SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52d8803cf616fa3d2f0da43b303aa1154eac8fb67e7ffec0b74be6804c911f9e' 
  AND token = 'im8+jLPUH/cxXjRosmIz9oUylvhm8vljGO5m1lO1moc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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