SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8591b655464e20bed2e5ea0e0dce9d55f5eeee0bbef2f6e7cfbad305cc448c21' 
  AND token = 'RDnYXJayaLxwWOg+Ft/eMQFJQj/sHyk3sKNeyFZzibI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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