SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0daee83ea713a37f9034202208f11af20379b965f64464dc9d8891a485baf129' 
  AND token = '9jb3FVo+K8fqHSjxwFdfXlVIjuY3BIDaveKu5m/3kg4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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