SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b48f496f6dad35096812956a664f1fd25dd3617ca29c8e2cca9d32bd2540c530' 
  AND token = 'iGWpjhhzt/nudQ3UkSwdpPEVClAteqWIZ/eNYlVHXlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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