SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e344fd798980fb6743a628869e1ed9ded0a72a3676fe443ff3b8f272282d324' 
  AND token = 'VNdXHDdJ5EwAmeyYXfShPGm8zPOu5sb9OQechutQctU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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