SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df9453fd82f7c171ee288d4396a3e5e3173125eb2cedd5ede9967d4edcc1f2d5' 
  AND token = 'OE/CxMDf8Bo8tHnF/uiJGRwuifjqcxyvwA5O0/w4byI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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