SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81dd65ac0165ccd1650dee8abec6b9baea6e63661ee97d9bd2e2b41cfab7105c' 
  AND token = 'r34egWYamZxJJJEnHm0pb1Jn3vmAuHQFaWkuxHd3SrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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