SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '802e825b83ac6873b3519f457b68508be556ddefa8667beeb93eede4b9abafa7' 
  AND token = 'NlGNsKu83ySeVxaMnyyE+StHhJhnngkToXxOmkKJniY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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