SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92bcf3583dadfc2b8a98c39f11e9c92191e85e36e919154806e957754f32b559' 
  AND token = 'ITfq/4wjsHuD9BBFFwvBWAd5apJ8ac0RtZA+9FzHULk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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