SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '50d595b49050e65037bc418c9251cf1b7a9a4de1c0d03fa28fc5e8f423c4dd4f' 
  AND token = 'lBnH9ECplcCPKiaJlcFlAOjSvoGGANsdg6tXWerJdCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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