SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b972f7115511a5e9073535a99bebdae72573f17182cb575455360a2d6c806c3' 
  AND token = 'FiLwE5iJzBfApzNTd/V/GzsXPUNR0z7yot5nJC9PyVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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