SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '456e1a1a3e4b60586c97167d895bcf84a6500040bb38e79ff2b568c3b1d2b35f' 
  AND token = 'Xu+vG3MQRMLe5cZY8UuLP/PAenjCT4IqBd2ksdr2Z/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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