SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89918eea74739c3442e2ee714058e26b8078ce56e7209787f8b2d97fe6d928fd' 
  AND token = 'nk8lJq+IVeL0EZrTR+wV6QWPxgRL6Egxl7BEXnE6rZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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