SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e42c720e45f7a42226e5d27c4fb674c0cb4e6a8b959cc7850d6f17b5f1692d9' 
  AND token = 'p9Is3CTfL8h8HJ+yLpcqAi33+5piBxaVAw9rt2yGMRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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