SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12bdbc22d8223c095647b43d2b740d8f01034f2605bf3880902b62c302767282' 
  AND token = 'Wkj5NhnpgIrtapOP/nE3+DcJufAQfE5ZWj+SCWBnmvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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