SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9437aa9b9889c478d14cf74fd9d949bdaf75bc3f465a8a25535f0c30e7fbb26f' 
  AND token = '778szgCgIpk66giCwrjDbP/SuCcXiAwctOht/sKLnNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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