SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad76138360d5a78d5022ad9943958a7f794bf24b55c1ac997a9632b7caf9dda2' 
  AND token = 'we4SnInpiPUvLXkiHhGZj5UI1CSP3wvugNw1a7Ks6Zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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