SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f659d2650d8f0c42a78bceef8245a00b12e2ee326e7933120de6382c812fa3f' 
  AND token = 'OSSn6BOj+e3RtQN6kZIoG5sa3Aw0Cugml2K5UWwP1OA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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