SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fe931e60be805fb7186c1f568647e2817787826b81efa1bdef7a4337fd93fbd' 
  AND token = 'O5lWAikvgr9FmhL96KXgz4qzihooeLK1PVjVxKuICh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00069

JSON explain

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