SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d83f9968413011ca1e489e3f0e3daee7036db9b525126b0fb3b38202bce74f5' 
  AND token = 'JpNI5gvXYuwHzDw/57zZVFsbh1LzGA+tWzrQQYz1udE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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