SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9804af237f7b5e556eb8e2d5bd9fe1a968f533232730efbc94906b10b83a9af5' 
  AND token = '62evsU3h4DMwps0YUckIE4dE6/GjRxjAyhwxoGgzTuA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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