SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a199dab7ab917a19ffc3194cd3a053b5ed8930c32848e394d57645f4c0e4346' 
  AND token = 'GM6/G63io29N8JGhNQUFU+nJdRpST2nb+lk+fK2F8jc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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