SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7ec5d962326843bad955d739639d91151d036116f3ce8173e7e7fbbb4f8d1f1' 
  AND token = 'KPkQ1f7HWvZSurEC4hr1n6ul3ScJ/8wCeoDP8ogoG3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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