SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72fe9cfd9ccebcf7ca6b872624032ef7a2d3bebfb4b23992f19fc920cc940751' 
  AND token = 'kMn5+D8FdehWflKU0HmgS7TZTRdnhTH2p0Q9AeYtDnU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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