SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61726ecc4bf205ad17800bbe4b2692b030f26e7097ccd87b201fc4fa4625a55a' 
  AND token = '5saEbA9KXaJ7xWFh//jrInUAJzKlqCCLsYfo8hN+tlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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