SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f6b26feac6057c30d78523fb5e17930bce31d0774bfcdb58ce055086c9b5bf8' 
  AND token = 'Uv3P5mATso8sEjwCrndKjZvIjlHHWk3U7KQnB3FeeD0=' 
  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"
    }
  }
}