SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9be683cf972be74a738ca1fe3994292efb4334561b7a58aed58fdb57a6c6946f' 
  AND token = 'o2nt2RjAOypmtwYIZ2evrRvYE+tMERb/gtxC9GGQETU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00075

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}