SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66c5bce7b4c420a7865100b7d79887e4449e4201b047416262badeacf5455da2' 
  AND token = '8sTRz5h+mGZrUzgF6jmIOKJp4XoiEGikGqrQNh/bzq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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