SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1570cd4fb0c3caff55d8d3b8b5a69df6cb1dc0c1aaa8bd174760643ca718e86' 
  AND token = 'MMD/OA6X2AN1ebYC9uuLXmZyKF/NPqhcNaylBj6zm4w=' 
  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"
    }
  }
}