SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cb82c3d6d48d1fff5f5f1a01766c0f4351c58f829383f09da72d04fe7d7a3a74' 
  AND token = 'yX3drTMLQbQicR7dTtkG7t6PhFNWkHI5CWbe8zgdbZc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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