SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bc2dfb575fec1970380b96ea13ffd0cbed954b23911803492ea767a6e0e0d4b' 
  AND token = 'Jm9f97mLgbg3KQDiOejQZdMNCiCyquOIVBpgTj7FKaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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