SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a6a49957dda0cc6856fab5aadfabf547a4ba04ed5ff195c92563a0bcf32952d' 
  AND token = 'fNGI7QRveHeGQqJHrzqKmD9V5iMRC0AEpGkBFcyH5XM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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