SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e2f893316e90f65a0f63e459e8aa486a95429d651b5a84e5126a675120fdd52' 
  AND token = 'Z0pV9GshzwNzmVkHUYZn4RMplpDUzBk0imyYravFzdc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}