SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7beda3dec0fb3024f67828f52463553c9df54a1d5e97e1e5ac07fdc0c5e9283c' 
  AND token = '8fTZeQc2GrS0sySUiPwHUXBCFytUyIcMmigOARPBCRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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