SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a8fb40a78777f176211e7b9f17158f994cb3f55156332341e11ae11e58d65981' 
  AND token = 'YO3OCF3B5Y64FxUYBOQYRmgq2XEAVmhEklR2P1//jsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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