SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b8117834a4b82dd4c8d8e627364ffd9fd5bc55fe3d63435ae6265b0c99854fd' 
  AND token = 'Ft/aY+JFDBeRmowVGMaZHp+DBjp4hH1aJFezAtP/ndU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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