SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2962e75ad13b22e40a1461aaaa769d016a9c529a224b4cf85f8dab6784d9591' 
  AND token = 'cMJuxaUchbQuk5bq9tKIdpXGVjd7feSOmrsKqKk5QOI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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