SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f13bde19dc0298f322be4aa442e80789ba9abff148525bf11b909b8a1396da46' 
  AND token = 'h4Pzh16KlW0/mDYNkfA5VjSGTcPH/yPr4/t0SJheBK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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