SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a9de25fe6ef5ef8560b490c2884a56552f3e0a22bfd75c0e599505ef59b94e3' 
  AND token = 'Ux2fDiptZ9avxKvJNAXnfYspuxgNbP933wDx+YR/Enw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}