SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8149da2bdef3dc88acc34f91095462d3657fea8ac919f90023fc3b61bf5092ff' 
  AND token = '/bC5KcK2FFa1QGz/SCp7jgO7AhCvmYtqN3u+Ph28wow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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