SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70c7b2650fc63cd5c59011ef11effbf32073aa6172eb630bbc2aa0278031b2cd' 
  AND token = '8MscRmlGUI8eL+YwUQFZ2v4YCC+Sw0yqomzHe0fMSL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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