SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6423f8b4f04bcaa78849c1f078f3cda5e319b88e4ba09e67ae99e8d65a611c82' 
  AND token = 'guy+FxNLdafQh42X/wR9U8SWBfpsUayKSw63YzLwJpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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