SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '30d84eb25ed05ca2345b711da7a393f1e2e90ab3556218a5dcc753d88395e94c' 
  AND token = 'oKjfBPxNwqmDNmEtUANOeW2Aj//N/mp7Xj4UNxE4a0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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