SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74768d9825d254e7fb90b99b9dc925b84d953bfa25cedce7c95b5edf841f2deb' 
  AND token = 'mlDh5bNdebPOGpzoR/jUHXq5rmrmh8OaUqj9OeOnfPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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