SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36a47fb2510966e4d897734f4e653c68b4255ade01841ce276b348c1851ffb38' 
  AND token = 'gOZ/s8qxxJ4mVRc0hWLbuox0Si7xlsry4dcM4X3EElQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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