SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c052c4dcbeaf47a781773f08bd3be2a61a4121b148758ca8033e22d14df6306' 
  AND token = 'X2jmdwGVvVDsY15YRUGtBzfefohHGdZj2fwW/bRFSrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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