SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35baf88188e1044ef56fb19118e10b42b8cfb783a815dfae510b9827f564c766' 
  AND token = 'ywUDuflIcGsl0QavW2Lh+Fs7r+IrNWQPvFOsFEYFbVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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