SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e619d5e6bc341562911e9b239d72dbca560894fffbe6f6cc7b7612f2a5f5352' 
  AND token = 'Zifw7x3VOK8UezVg+IB9H2ZcJ+JoN1850op2QGRWqcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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