SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9faf79386dec1a74843de72b11b9ca47451f446adfb61a2641a5849dd01aeede' 
  AND token = 'IJdv4ZkeMqQ9qGWHaoWHkldrK6P7SyztjpqqXfm9JOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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