SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b5e69a200e945273da85c16a181cd14317fd05208fdec59e1545e6f4f66dc7f' 
  AND token = 'LRHj5fFHSEkpnEh6KJJjLvpSNz2gV9VjnXBx3DfqaFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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