SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8603df3cad17b72083e853b23e49c544f0c7ddc083744b6bf027742b288afee7' 
  AND token = 'vtOnamnglVGgnxaAmcqUP3KQzF7H6FhTRPJbhAq/dAw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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