SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8481decb1108db0a102e215f142a51da8745ef5af0aee76554bbdbebd4e6c6cc' 
  AND token = 'RqCzFp0K2//qHvfqWfqQCtc8YgXhiHHpOoydwemakuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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