SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7a16353e2f45e6898888a1e7e2d9badeaf548e1d21327094624c6da03abe03a8' 
  AND token = 'ihZEDpC602PnIcKOAAkc+lEHzNPrv0FpBNUiLt7TTEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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