SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d527b0514672e66560262e2dd7fcfdb69a7ca7569051014684b1713a012dd93' 
  AND token = 'hQ+XsLIbTwQt+pkReU8f+0ZWUkLZ+k7H92UWA+vFS8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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