SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f38dc58503b7438190752224ecbf38b82f2536e7b41f0333d5cb199eadcab8cf' 
  AND token = 'TfJAhegq+Kbzy/SsmnBpDQuSlHbHIHYaKgbofo4zwoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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