SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be340e1614a1323ecffd7616f3cb3fac7789b5b0dfd1161adbb94fdaf735f626' 
  AND token = '2lH/Q3qHMptioInl5xpWXZUT7EKgmcWxQpFCDBvn4mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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