SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bbf3c56ff038536da74b525fcecf1732cd95461df39c170ff0cd155e34eab68' 
  AND token = 'UsRc24KJhApvoxYYCZ81bZzqoiNGeI96N+/5AX3kkDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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