SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4eec75f74a536de8175cd42825e6bac388f0525c03856b5425e696c0fc82a707' 
  AND token = 'NCDyBb7zUGAvfOmQWWh3iuS+vqKxZCN9zCIrTA0850Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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