SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50e92e5f8d99854007b75289a33e2f9739e8c77ec6a0fb551d5c62698d3bfefd' 
  AND token = 'zsPB62LOYD7lihfg9QI+qnzBjkHgYFYHWfK/1ZuIpZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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