SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dc33858a83af3e54251840889faae08286a4bd49511e2d4457db6d810b14b69' 
  AND token = 'sCxfwa/XCqDBu25KuTRFa1gfuLKPS4om24YVJREjMIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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