SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf456ce1ce1b8b975aca153a491ae0a4090fc0cdb03fc92a01f6b0ae279cafed' 
  AND token = 'QWwy/+ELZSPg3OuNqnjkOywOvTEynPyqeydfv8pSpr0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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