SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '944fc4adebbb22437c638bdb214b0204e2a5d15b1d6e628902acab353d5ccfa3' 
  AND token = 'zziKTYGmoeolQpXaPzIzYtSnlwOt01YoAcaHEYu9FSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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