SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7674ca6b77c852ae7dbe56ca3b61704b9381314608d100c736742381af45722' 
  AND token = 'ZRabwp/r0qyyJaRHhvGoxjN2ZmkKX7Be3ZryR41gArs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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