SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea9d5e262afdd781a999f3520ffd8843136da7a59c75239561f990cb0a95f768' 
  AND token = 'Wy38YGwkTFu/+PjLtUVzTlkghZMYAvLH7NKR4E0ez+Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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