SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f5e9acf3ab635c7ce040c348fd777216102744c0651c86b800811bb3b9af5b06' 
  AND token = 'l7GElqH/XdN59r6g/rtl5EIsoU//as9RwMXHFirPb9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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