SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e23e16045045a2878c91525f59c715278512c979279ad6848001778230f8e1c1' 
  AND token = 'YzMiZ6BRdS8uAMd7wyD9CFuFJPBVf1Bo1zTVFxXAXWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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