SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '32a3fe090858f0742f4ca577df3e39d4bb353c8c4f41c610a00775011cf20aa3' 
  AND token = 'FvsYK3iC5uze05MAjpFqI+WVhxlKhE8yNsnQOkzXVAo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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