SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30bc548298fa9847de8b48b1e0f814e7b551964c77b745995446ee1473437fcc' 
  AND token = 'pzlJSAXlW2RVitSXrG22+GhsjmgIYPvBOEv0twPTtNo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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