SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4288d57152ed72f2fc63aa4067a2fe990928ac8708811899cb4562a6ee18b88e' 
  AND token = 'Dxd0hqeQAsFjGid3PiFlQsgL0FKZR777cGPjlzThDJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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