SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e470bc9bdce9d4081342b7a5b343601c5463ee23a06efdd62a965fdb9770901' 
  AND token = 'UMdSJeDEx6ZrMq4QNlttOjC6OaELFxYjSsOaQiqIZxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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