SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd2b7113d64d1fbe80a51c0c5469e48a1478c90c7622f056a33c8919a5e2527b' 
  AND token = '1VbhS0+FKFwKhIALmKB9BlWzaqcLhko1LPzoKR5CRgg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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