SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b86e27a9bd2151f4badba2ca3f3a9c190d150943e31f2af76690bec8659da83' 
  AND token = 'fZgt6ItL1O4+hqksfykNnVf1KCi/pWEtnt4KYI53HDQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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