SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c830265f66fd3cbab8d5817cb4837e7ce6a9f3b05ae87de978c2cf53ca66b4c' 
  AND token = 'CVupqw+mZLKr5JkFl3gqTthX+PFiKbznueH1u3LoX2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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