SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fb68331f9bd3c4af3b234defeeaec2c3191527f79a6d0a61621de8f9615b979' 
  AND token = 'OeiNcRuL4wy1YRpB376NFDzLfPLJNQEXlzrTBK95JRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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