SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab38b43c0a87934c8a4ccc1fa22b7e9cf3a78983d943e6c50153bdff28e1d092' 
  AND token = 'hQKM+lDwfB/ZKXajPf28+T+2VmvpY2OgzEDcbTary5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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