SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b1f4688ef7d3dafd8264deae4f31bd282145fc04f9d45cda24d23620c287a3d' 
  AND token = 'pPfRo96caAJcbjePiJbQZy1xeubUnQkNhPVMjS023fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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