SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d83ccb9800f63a9ca43a37754600927178abef62c14e66016a75ab53812de4c' 
  AND token = 'YpwxM4rcKCvqgiqiuQb34aoiyl7bnniEe3krmTAinPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}