SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '668ff78d8889e696c187f09d0d0333911f58fa99a07a6ac226bd239d54eb1987' 
  AND token = 'CKluWjbMgHACQYxHehPmR2fLNaI5B0EwB7gloy7K2Ow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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