SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e66ad322dc504ebb6c0d473023fea826eccce4435b5ac879d5c9f59e429ce2b0' 
  AND token = 'UVAaoKneBtoPMYl60LkDuQh+a7PEnYRKQMy3DMGIhhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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