SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3a410362cecce22fc367336a410974e0c773d7131b6521872ba67e881316b25e' 
  AND token = 'fi8HjklNYiUUgl8r+uJ+S3qvCJjFtlRcHIS7IAl1VBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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