SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f7b461ef9324756e03d87fabbf959686a15b9c442532ffd8bafc1f9a5f6845f3' 
  AND token = 'x0F3A+BUo9iAgrcY7F35TZ8nNEA4FzMCJqB1BoG4+1w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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