SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc265823e1a74af0f738bc91c339e68d44e38c1f6d13762a80f08750ef12b5d4' 
  AND token = '+BpwFlIPu/uYOg5YOaeLppJME1gCSOGGFeTtEptpvBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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