SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a771d221b220c5bea58830e55547d1e3b5c0bf95922f21faa0dc17d518742609' 
  AND token = 'cFUGEcOB3geIsVU4qEaxKIyNm/uIylH18MKWHDCz2jI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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