SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd5ff49b85d95ccd1b6656793ee729442a840cc4e0bf542392f3d0b4aef4ffcb' 
  AND token = '9krzWKsdIF/qCZVJXFWGpk7xkiy7W3+T1NRQrXOqqvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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