SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '271d24e928c3146344e65ac9ac178aaf32acb54b13397d9437dda0e5d5e1bdeb' 
  AND token = 'ZNpQZjXPM3R7HTqUxv78wvLXUilnXXINUMjFbCSC3K8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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