SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5045eec1a061c8bb906ba568619bf007276c6ad0207dd7795b55d65dad6674a4' 
  AND token = '6lYh2/GlEfSvjkiOg0cReaixIICMrxKnEc2PX1VQIhA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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