SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '684691bdd184118850145c05faffe7ae928abc96f5eae388ee47ec485e6ef131' 
  AND token = 'tkS0kS/1riqqC6+T5w68xqj2zPUnrK4My564CiUDF+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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