SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '451a2804887004edfe6ff9d5f8a12787ab3d78049b3dce03f9123affc99dc4f3' 
  AND token = 'ZVzihN/lAm528XH1O6/oBw5A7PAjXGMQXSPdNkWucE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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