SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6628c476d9815bd4bfcad1e97239c834a4e3adc73daaeeae5404132888ae7619' 
  AND token = 'IrbUoLYTRyvPwp98S+CsOkZEx5TthxpNYl5BgQSgB5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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