SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b7491f7742ae8235903fe50972665e022dd49ec031af3c4f3e6f035dc1b43ad' 
  AND token = 'yWgZmwohO03wGCWq/oWXeZHRcnzIOJFy+uTeYAbXkn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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