SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd5e5b5e86c3da5a15f19144983bff2f2b309925a4739472bb71683dee740c23' 
  AND token = '7v9j+3kwlEj/juDCExYtmNBjxmtLwX/TmvK466h4vMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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