SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2672560a9bcd46cadcfe4c39fffe3a79c0faf52b3ac2c2f3e41736b5eddaabf9' 
  AND token = 'eogn8BwPu8uxEdyLlo4NI2tTw6kwWznk2Ia13PvWzzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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