SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4968844315debdd9e984229d58ed287f909363998e3d1c06a8a79eb9395b5a7f' 
  AND token = 'jxtIN6qqTUubTxEKP5+UGqnUZSVXYwgBarh1h/AGJQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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