SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '363e03d39f20691741e95b9b89cf100f766443770fdda9068af6426aa2e0197d' 
  AND token = 'sn1EjmTRqCsMEsgj1tBIhEDFsiP4wNej0WUMLfskPIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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