SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa1fe8315d696b6ae0672099dbd202f677eb2463aad1a48a0bfced699037f901' 
  AND token = '9x0bseNFiVHeAtb2bwIcoenpn5pTpPdH8nhYWuQ6a8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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