SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '412d922c012a687dd1a0e9469b07de0e2ce1f64a56f1adf1e2e351bfcd41eb7e' 
  AND token = 'nxBsxvg5U8CGDUwllM+QYUNLjJ85+zWrh+94qrDmPro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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