SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '421205a7580d532bbe13b5112db99c21e602f4ab5cfc81353a980726d540c16f' 
  AND token = '4EdHz2I/juz7oRyNdfi8PXNOhqJAJ9Uq5WNJ/096uww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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