SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2e0452ac1d452f77a2fbf40e789c4ef1e96cc8e8d665c5b3a7d46f5d2cc4755' 
  AND token = 'xZEJ7rIgOVQ3QyJKJMoqz9Dt5jCoR5GdGG+RNCxXbhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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