SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d81d37a23d63d3be79574e23c8e3481d574d616b89fa49b516d265fb9bb3f60' 
  AND token = 'cz4RkVc+VMutb01+JJGjFw7Wfzuu440YAqx+HB+Ps0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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