SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e6c48aa0bb992e7dde155a9edb6eff3b638f5d97905e9601e57ea86c9e4dbfe' 
  AND token = 'fVP8yCwlOxv/CnQCaB1V9xp7zXuyPBLvJ8PGWq6hqjU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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