SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfa7fd584653737f1e30aa50e1ed2e3504a1f514c910fdce176db4a9172826b9' 
  AND token = 'uWWBd+3VtjJQtznm7YyeZHl62PKJHpySWtHyXUOOwMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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