SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27f25df6c773302430df543bbecc2ab331eebca67ce48a6a8a4bcf89c556e672' 
  AND token = 'v2/wNSKNtKtqE6tNYwaQ5XxccBGmhPYWMsImnb+QPAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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