SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f4447231178956cb5ee4a3f2eee6780c5788125e98acad7963c272198057117' 
  AND token = 'Y9n5zhSvc+FLzlboEee1FOYa2XJnhszEIHWF4zF/WMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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