SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3da8cc4b31deb985b618986fc853aff77e58cbb4c580e24c8b54ae8f6fd3af8d' 
  AND token = '+RdUbVUMeYHBnn1OxEoYFxaG7HZCTtVQV860w7sgIkM=' 
  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"
    }
  }
}