SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d0504bdb84b388ca84d332e054967e6fa99774d86a5f7e6441bc1b533a4aa39' 
  AND token = 'wOcrImzqzZUyDMsh1VFWUtVKujo82WxsS3P3KHv5jMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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