SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e223a88263ff1f64b6c7d7cfcd722daeb1c62824541a5e1641c593dcc82f9f57' 
  AND token = 'qxuKb3IkWLgQAqeRIMMWO95/ADiqJ3s1VpXJyFa8BFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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