SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a2c400cc51495e67ce5a57bddec199c28ea69da06c10118fa45f626db3bb050' 
  AND token = 'lwJvkN6SrBuWEGHYOynggMSeX5XPhUTSQxduhIsxSvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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