SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '205adf50355a8a60580b3447192e5ca1f3e5bf9706826beee6b826dbf026f1f1' 
  AND token = '2VDG17AFjSdHRkDliUsXnejN58gfpAX20jA4OQlMTFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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