SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '498fe8caaf0f69ace2e815e69a4bd6ff08bd6f6e43601f056e1abc414550d5e3' 
  AND token = '5f7xSEpPc2PNUBH7PxRJ9kKMUyfJ2RVjW/mhGJuOd60=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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