SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1952700a21cfb81a143635c833924aa30d3af69965b1254e787384d975a8fa45' 
  AND token = 'ZTUvEUQnKDanlNP1t9Zoxq8EARa2PkfHP3uPiKpsjaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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