SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec62853b58555d6fe9fb30929471d7344d8ea0f0108a9fc931be4423c143fce4' 
  AND token = 'XPJT5oEFyhdXG1M0vGmEhW3fGlIeLUYxswSTSBjKspk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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