SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e75504f9440c1d77b8c61f31dfcf238f4f355575bc3e854eb952ed76d241319' 
  AND token = 'WPgAy9cnRyplMJ+4ZyNqav6pn5WhM8BLs433tOOJMN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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