SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3242713b9893392b66cf2848f5f47ec89851e17028c34e35f148efdeaeb7a40a' 
  AND token = 'vo0IBt7blbPfot2EiZWYohdjIdZRMisIf8IPhifvxdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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