SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc585980dbaa70a98b10afff5763cc9850a11a50f9dc0a56472e987036142746' 
  AND token = '5IC0oEr5YkHsDXQAlkDtmmueac7HmYDU//pzHHk+bCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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