SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '68f950ad0f5134465f1c52b14c85854cede1cbde36b62284ed3681bbdc9dc701' 
  AND token = 'U+kGWb0HYDxRD1B7uSIscvk1BJR2Jmt8UvfUyxtujCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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