SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5ef4410584ca580f671552c430ee2e6acdd9e7eb0fa7931c6a84c4fb79516f3' 
  AND token = 'xtCOIpnYwOsx1ig2KP+qPgGdqg+YFYtXvwpJ5H1VjAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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