SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77ceb0534274614c917da5451bf95127a31d783cb40e9d8e414321fc94058b7b' 
  AND token = '4EDlsFBpQ+3JhoDKkj7O5uRg9Z5dy3J13ys7VGYUE/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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