SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '856e4c248e10c06a05a8e08845e1f4aab3d6841aecccbca4a4b4a3c05d9dcb2d' 
  AND token = 'qwbBtPNHiHa/qouA6WvQ5xxeeq360xC4+mhGdBrdmPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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