SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f2f0637801f0c4dd68526ac6aae339917fd0f53e68ced15eba4d4b60671e2c9' 
  AND token = 'gqFSTNMvJPNUt6uLBY0H3TSDn0T5rl0crFNnSsa6Um8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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