SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6331a79fe5497e44c0081559696a52bf304110822ff76f8eda3283db9598b468' 
  AND token = '+nR1MXvw3ec4GKmXyKXZi7uj/ykityaX7YKd6NOZQJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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