SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '335b334ebeba2eacfb61565efabbabd17bd07cebda85f55828f4013dd8767cca' 
  AND token = 'w0uol5rHA+Lo70BN8Ng7GPknA3PWmPUH9gRmlvmaWNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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