SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '646a46b198090e88d127ef4e958d24147840e5822317e730f1e132aafee18b9a' 
  AND token = 'aKPsWXXHKmXO3f6DGqWxNn3k+nt9AFgShKrbSFRd5n4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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