SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be901da0094251fbaf3d5361131ac7feea06310d8f6f59404105680a93bb7449' 
  AND token = 'vJleiBnpizJtBiyM3i9k881OIjUCM9dne5B/qFUnekU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}