SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c6447d2c0654ee93319665a3f201bda25ea5379abf27fcff6f654b9d0380625' 
  AND token = 't3TDJOSws1VLnKOXrC8s+oPYFYGP5Gcn4Humlk9AAGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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