SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29a9e7cb24fafc34062a4a5b2945f3060cc9d113d3ee89fec05c4e856473f66e' 
  AND token = 'UV62OrP/Qo6AKZHWTs4sxg22h3cDyy8/VbQmuQI/B7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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