SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b40274cfd3e755fd966cc31c6895a14212c5b9796692d38a489690868e9f705b' 
  AND token = '744NhygIIDoS8kK20rYlH+I5CWu+8cKMNqqr16o8ASo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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