SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eae7d09cc3273bcb04314ce4ee57719fde5417758c9fabad5fc8b34b895a58b0' 
  AND token = 'SxSjDdIfRhuoeCRtuaQLXiSKCvRORx6s/vQWAuOkoiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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