SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73c12abe02e6a17b18673570d309de0da120361a0aa8e7b9fcb3a51425a4ed2f' 
  AND token = 'fZSKMgvVrYelfijbchfdEhzGdOUp4JEDtuMq7eiJwk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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