SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cd9d616fb153d53ff89254b0455dc7a10fe8835b8fb74df871f9e5f8b893549' 
  AND token = 'rhObyDR6fyQD1CmrOtNk4Hq41Y0RRnKSXlZsrCkHgKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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