SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e043e3e080a4dd47245a0a57b656694500bb520004a27c8f7e6691896bec112b' 
  AND token = 'OwFnZMVZJOsCYKWvAJNxSj+RMJPQzLoKRsgL+Vf5Guw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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