SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49b7a907fec5a6190753db762a987332997477d6551e57340665f10c18a57746' 
  AND token = 'kp9LDB6AXgyftFC7SMp7JWWN9poAvq2j64s8XVc8hmY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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