SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef103d7d3ad200c6cfebb7008bf6df6635f93f2f885392947a662bada34aa7ce' 
  AND token = 'VGPbz+YEFKlzqTmogtxTiRq6FcRoCKjwDf252TynFjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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