SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dcb457a069d07f1ffb721a2f425389a507a1b5659436382a082f7efdd17f0aa0' 
  AND token = 'gS51wuPmUic/3sgnF4vmTNkSK4mOkXaa4s97L90OMwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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