SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '848660610885ed1f5a7e61a3e622217bfbfd8ee2b1f165b7030a079bbf6353ab' 
  AND token = 'O9HoLJQCymntDQY/5TzP4KeLa6WA6swp22sVwa0qTd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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