SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56594823ee4af99e831e14bd6565560abe6bfce605d1274c288925136cb17a43' 
  AND token = 'hdpurO7bGJOZgdlEnvE0ahQGF/SQdeYzCy4XOKcPKuQ=' 
  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"
    }
  }
}