SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5b42007f9d551d7f60851f22bdf6b9748d359fa2e6da98985232772c4c7afbad' 
  AND token = 'JJn7cPL9HpK4iI6YPp8+h7AjZF83sLOF3b/JB3wsW5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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