SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f2611eb93f880893c31594b93ec68883d4480b17dcab3cbcb252645f161f452' 
  AND token = 'FyFZKmo1vgicENVy+2CEEfAeeZIarKhfHKKdNbfbh2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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