SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb30a7b797ecf0a74642cd173c2ab00cc47d8f18fd4a92e2c70c797422a8d9e7' 
  AND token = 'Un5P4LsdDi25nMNjaFdUeNQc368ffXWt8k3CZ0BduOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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