SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91e62bdd51621ff6a4fcf79a95817da40b1c72fd641cd4f7c6b852be5d8bc535' 
  AND token = 's5JPG3I3F5E2Kpv9BJyiOyljU3e5YQQjBVO7YP+0JGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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