SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fa73e69561aecf56aef5b9ace76bf41cbfc342f42c7e0d9772a030a4411406d' 
  AND token = '4CX476iFTLoo3WvSI2oYSW6W8BbrSBQj6fMGxMUAJjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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