SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdaf34abbf5faf548736d2be08f78fe9588732c164603e98bdbd631bd51f7a05' 
  AND token = '6MXSxAC2FRftA/2aLc4Cwdbs1hO2GCQXSkkfsltnu2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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