SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0500ccffb33bace2a57ae810f7a1b69ed303236275d95cf44e24aa6aecdc98bb' 
  AND token = 'K3oMNLE4elbMpHLWlpEmX7tIT/ebezCxExBwEgwyY9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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