SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce14d8e9b54f60c61897ec100c7b8ede7a5aac1e29ce073825879437bbb8683f' 
  AND token = 'V/Xje+6ZdwBya5ZrwVIYKs2uGkVqqfWfyhAnon/zCh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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