SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c33548c0b04a683fcdbb240ebf4ea160d90970404c10dd8197ffdd9218de07b' 
  AND token = '/qG48EvyIw2TyMkDUSFjRumBCoKxrWBsayJUHjBcTxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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