SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dbfe8c89c4fb60426eded87aac0461b35a235008d9f07163af9c668ac2f3635' 
  AND token = 'hK0IAFW+zYLSgJ+wxFszn5YYKGfv28tRexgZoTQ5N+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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