SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a3a6caaa6ea43dc4e32855f6d8311a928ba4ca327222b46a7d13bb07d348c74' 
  AND token = 'OSS5klbLvTHqN3CmOYp3fRvw0AA/pmigUu5gXXdFJFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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