SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9b1fb6fa925c4192de24f0a267da18a1855dc61477ffe57a657eb2d312ccdbb' 
  AND token = '98hQK6on4gsvnzUpN+0VpWlguuFmZkc6DzIoMGd7dI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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