SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '679b0ba79af588010e5bc90b7c4552551f0f65a00b4be7d6451b078a90deecbe' 
  AND token = 'BKpo3Krqte7u05D/qFzwTes9vSy5xdvM0gqiEaufQfM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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