SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f064efd20ab33f0bf4587b96b23c08d129afe86d46237657cbc86e4bfa6f7e4' 
  AND token = 'HuXiBOZk5zVnRSTMenZhke0YMFdIyhsFWE9uc+Y6sPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}