SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc6cbf7b91a19696b52d1a3c3d48c789a0bc60c90c6bc7d5ee7d30788a926bf0' 
  AND token = 'F4/TMXv0vZ335pJFxvnItRFYJUZ+2uLTpwS+JDwbe6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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