SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10ffb72477f3b629c947ac8687a7952c9671202de721cda5e16f116c54aafe12' 
  AND token = 'VlsOuVgHr9LGhZm8F5xkORgMd01RbD3OKDhdRXlv824=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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