SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e3ea64adb2fc70d5d5c1bc5d7e2db0a32fb6701f93f8eef590ff653a355e6ec' 
  AND token = 'ZIgU4gGIv6BHmGQZZVBKFJvAV3izTWZDSj5OlpxfMBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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