SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d5a46125cd077cc6dcb6d225477379f88b16243ab75af1ead45bda094fa44a0' 
  AND token = 'AdYrJugVhgIJre1Z25zFOnIuHGyKlzwpI+ppshGDcWo=' 
  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"
    }
  }
}