SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f947293913fe5d11390a27a167179e47e010634e8b23f2921f8d0641365f7881' 
  AND token = '0JEdSwWw87JyujHgThB4J913iws++KoFV+ZdGFgYIqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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