SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f6a5bcf07fd92bded46ebdbd0bdc0aaf1488933856a02fb9981cb40be45673ea' 
  AND token = 'kTy0VJxAC/DvYmYUiNg+6yLTK7jTWcYZiVurhPZ75j4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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