SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86fbe35cadf8701f701c49724c9a35f08629bd0400383f8075b473e016668716' 
  AND token = 'DE+uBrbElszKmHcKtO+jdwkWLWqpvKLePMQ7qJE6fZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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