SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81e98138bb7486e74418796450196e45970dcb936b711b6c78aa6dc21b8f6133' 
  AND token = 'foBZnRHfwKlEqG1UwBbJsC+AreGUe2DC00gVuoPafss=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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