SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e23475645d56ac5f93ba997dc899f088ad7be9766003fbc71c609b9edb9dc3d' 
  AND token = 'Ba40PCYc7CkwnlLwo92kMm/PKhEtYYJYvPQ/NBktq2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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