SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bf7cacdc6cf94a29951c5d079d656e5bd3f0d38b07646576579067086fe5ddf' 
  AND token = '3hL/RVxqCUvg/aAwSZWhNWardzGKppopWGgPR6AbHF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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