SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0af8714be3d39c0b4092373641f9ed5ac705d4f0462519cbcaa1efa344168fc3' 
  AND token = 'ZEFixvx+Sr0r7lnR3EBAccmZOqjVXrFq1RyRBZafvOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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