SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14d29a8e6b53b986b18b77e28f67c3194459c5fb0e999672bc69d819a302cbf7' 
  AND token = 'sXYZlTUPu/g+y9Jj5PjaJKRTqJ24EnaS5/bIdEJAQNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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