SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98bb52e326307dc93c51477538f98e2821657209cbe50a7619f408c7075a9934' 
  AND token = 'I/r0Lm6DkOUxKG+obF7hZ5LEkkCfwYptRqxoldUAcXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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