SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fba214e886c88fbe9aef469625fd0968bf6a18daff2d024c72444960a3991fe4' 
  AND token = 'qHP1SH1RaVWCYWDxK5PbjrShzPv7tdn1LydhghAqxXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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