SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44a17bafef2400c341d8b5e91991d7de5b1fda5a8e491dccbd0418aebc2ebeff' 
  AND token = '0AHJG8fyGmlyV9+ZWjd+RuvvYS+Tys065El5tWEhvb0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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