SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '490319d1c7df7cf9bdec2a474d28fe974b124cc5dba89b695fdb3cfafc7ae4ae' 
  AND token = 'M3/XoX9KyKZ/58diaSr62GdU5ppvtRtS7v54zUyTahU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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