SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53574f604a34221fd76b3a780289b6d0ce81ba8ab59b7435019cf995f20c142c' 
  AND token = 'qRqt4NFe5BulS2eZOj6zfMGijkZemUCfIdP/Mb/ypTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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