SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e08cd0882cae1f99bc102f0968015b75557b07a5f7bfae027a7640dacad0c4bf' 
  AND token = 'LJnW4zFKVqnCC+XqEttgD4SMXQgfGuHpxLa8zxVQ2GM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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