SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f641114387263b423954d6d74a75debbeee6e2e20ce0aeb41985e5305978236' 
  AND token = 'yUvb4fQKWf9AlmcJIZCiuN9kvZpgRipCE/Gsn28yVrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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