SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '626242cdcf11a52c43132baa4e577fd95593132b8fa5750e24141f41fd36eea0' 
  AND token = 'a+usfwBltt8DgZGaPn+ZRCmJZt+zzDF3YJj14YkWn6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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