SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '019954b530cbb407ba80c54d2ff18b72fa87659c0057a3d07aa8f032e5e2631f' 
  AND token = 'VKKTGXDaiPcRr5uRhvskgYY2LkZwq56PwVJzKfrV+Qk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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