SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f9b328157d7bdde1a4da305358788dfa608428d5a8532a73ce4937031186b3b' 
  AND token = 'PNuWEjYISbQiLGl/I/UXmnz79pr1CBsTYeiKce+BdMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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