SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3ecde630df45b9de304975017f13e65366e4f7a983a994b8d705ffd1c5ccc96' 
  AND token = 'VL0QGRdIWIym2hRHUpCiUoo1gMO/ErcZB06uriJ7HgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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