SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1ca5cb0fa9778bebf31a877b91af1e982aec57c93462ed9edf42655a044a0978' 
  AND token = '0WixiUIJmKATiND4x87RoLEgcZBbhuAY1azYSyzfeIQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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