SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '686f3fc96d0c9bd0c351bacddbbedd422e0ffc3df7134755100b92515d78f27f' 
  AND token = 'wjO817vq4LVvwJXaL3VBvj+ZDXihzpl4PMdEIULm28I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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