SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b943526a2284c5b23a6e110cd2a53fda39f50facd90471f36c084e52ce485b9d' 
  AND token = 'wCMAd9pWXScofl1sjKCVknUwzlb1479I69EJli67r+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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