SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a568aa3d3214bc4939b55b3a983f7afc6f5ca5e79540e6d60725593646dcf2f7' 
  AND token = 'Updy/LcS5wIVXfOriOuPauci4upOz6nZPpEsArQg1Fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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