SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cb6e5c69d9147714b8c0e4b644a43755ee210c55bfb4dfd9ca805b436eb455e' 
  AND token = 'beSf/V3nyz9OXHl6ZrgHvsFYSJm+DhGmkHedwk1pXBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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