SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e48bdbca5a88357137ba56741bce111d8b353c1ee9c931d1063614a9b17fa17' 
  AND token = 'nvoJMicv9d9uC/+Qz8FLgwIlLTaHwE+x/8Qdlwdiv3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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