SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'debe492ee35d91051bfdf24ee4c8d79e024ab35602529a7b3c1c041f6cfb4d7d' 
  AND token = 'fgZAp7P7ri9uFum551wJMRhipBaDzGNKokjVktWrNpA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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