SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8626db6acb9b067bff51a7ef4da9c259d0ff643049efef4b288600a9712e05b' 
  AND token = 'jjvqjzm/+sUMnU+wAPtcas3iFGxHBIvYh1oM+rkUiyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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