SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14c50c976a981096ba9631224011d047a9917817f0e05af76a1a2b62180b5a77' 
  AND token = 'nKmUdQJu2V7D1KI0YUZ2rdK8hZZxW7M5PLXEL3XXi5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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