SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c86f91a7888d0c3df2006a4370ed88a8edd7f565c41ace40236979658d74b71' 
  AND token = 'HujThJvkreNWgDY9+OYGVe+sV8DdXWCwENeWJDiWH8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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