SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cdb79d079212cc65241f473d3bbfdb9d33d1797fbf01029718f41e79d65f141' 
  AND token = '9FbQTZwgbTF8SIF89BO71Kmc8TzwqgHdsygyJVtQfBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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