SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd97a039d1ccf91c3f0846f9f64389c58b7ad40e065c4da31fd0853306e3fa7aa' 
  AND token = 'l9+h2MtrAfBIwar2EhzlyLhNDiaL3rErYPpiX+68lEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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