SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '305312d076143b497c446834e8dba06067cb09394cab525235c98d7cfc91ac64' 
  AND token = 'Eniogrx3LM6WdcgbP4ra2/Y0kRlrq6g2MZexu94yJxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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