SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66c963c4cd1cab7c26df7479fed865395be167cfcf43e52af3894dd7794cb977' 
  AND token = 'vlh44j+D/07XwXygaIJwwS0VBkFXVkBx/8IJwrShhjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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