SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f648680509948dfd12223f0e064380e562012f256d68bb8e0d9c4ff456e3a56' 
  AND token = 'sEkTdAz6W9/WkeFLgljdD6CvOUoMrndVKHzSoa68idE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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