SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23101a19cc252edb260d84b84623743fb924de85d09c808ff2fe9faebf048dfa' 
  AND token = 'xgmP7LzmiMJOT+ylUCzdV8NzG/1mhBOlq1j8tWeBOmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}