SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ac849ab3268666cefd2eec272af68851bcfb9e71db2a386ac365faa57e8adf03' 
  AND token = '5c9H1I96tpXr7Yi3sLFckrgNr63mi91swEjfyy5A6I8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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